Instruction:
Implement a Python 3 function for
building wheels. :param unpack: If True, replace the sdist we built from the with the newly built wheel, in preparation for installation. :return: True if all the wheels built correctly.

Response:
def build(self, autobuilding=False):
        """Build wheels.

        :param unpack: If True, replace the sdist we built from the with the
            newly built wheel, in preparation for installation.
        :return: True if all the wheels built correctly.
        """
        assert self._wheel_dir or (autobuilding and self._cache_root)
        # unpack sdists and constructs req set
        self.requirement_set.prepare_files(self.finder)

        reqset = self.requirement_set.requirements.values()

        buildset = []
        for req in reqset:
            if req.is_wheel:
                if not autobuilding:
                    logger.info(
                        'Skipping %s, due to already being wheel.', req.name)
            elif req.editable:
                if not autobuilding:
                    logger.info(
                        'Skipping bdist_wheel for %s, due to being editable',
                        req.name)
            elif autobuilding and req.link and not req.link.is_artifact:
                pass
            elif autobuilding and not req.source_dir:
                pass
            else:
                if autobuilding:
                    link = req.link
                    base, ext = link.splitext()
                    if pip.index.egg_info_matches(base, None, link) is None:
                        # Doesn't look like a package - don't autobuild a wheel
                        # because we'll have no way to lookup the result sanely
                        continue
                    if "binary" not in pip.index.fmt_ctl_formats(
                            self.finder.format_control,
                            pkg_resources.safe_name(req.name).lower()):
                        logger.info(
                            "Skipping bdist_wheel for %s, due to binaries "
                            "being disabled for it.", req.name)
                        continue
                buildset.append(req)

        if not buildset:
            return True

        # Build the wheels.
        logger.info(
            'Building wheels for collected packages: %s',
            ', '.join([req.name for req in buildset]),
        )
        with indent_log():
            build_success, build_failure = [], []
            for req in buildset:
                if autobuilding:
                    output_dir = _cache_for_link(self._cache_root, req.link)
                    ensure_dir(output_dir)
                else:
                    output_dir = self._wheel_dir
                wheel_file = self._build_one(req, output_dir)
                if wheel_file:
                    build_success.append(req)
                    if autobuilding:
                        # XXX: This is mildly duplicative with prepare_files,
                        # but not close enough to pull out to a single common
                        # method.
                        # The code below assumes temporary source dirs -
                        # prevent it doing bad things.
                        if req.source_dir and not os.path.exists(os.path.join(
                                req.source_dir, PIP_DELETE_MARKER_FILENAME)):
                            raise AssertionError(
                                "bad source dir - missing marker")
                        # Delete the source we built the wheel from
                        req.remove_temporary_source()
                        # set the build directory again - name is known from
                        # the work prepare_files did.
                        req.source_dir = req.build_location(
                            self.requirement_set.build_dir)
                        # Update the link for this.
                        req.link = pip.index.Link(
                            path_to_url(wheel_file), trusted=True)
                        assert req.link.is_wheel
                        # extract the wheel into the dir
                        unpack_url(
                            req.link, req.source_dir, None, False,
                            session=self.requirement_set.session)
                else:
                    build_failure.append(req)

        # notify success/failure
        if build_success:
            logger.info(
                'Successfully built %s',
                ' '.join([req.name for req in build_success]),
            )
        if build_failure:
            logger.info(
                'Failed to build %s',
                ' '.join([req.name for req in build_failure]),
            )
        # Return True if all builds were successful
        return len(build_failure) == 0


Instruction:
Write a Python 3 script to
yield names and strings used by code and its nested code objects

Response:
def iter_symbols(code):
    """Yield names and strings used by `code` and its nested code objects"""
    for name in code.co_names:
        yield name
    for const in code.co_consts:
        if isinstance(const, basestring):
            yield const
        elif isinstance(const, CodeType):
            for name in iter_symbols(const):
                yield name


Instruction:
Implement a function in Python 3 to
return the quotation between two currencies

Response:
def quotation(self, origin, target):
        """Return quotation between two currencies (origin, target)"""
        a = self.rate(origin)
        b = self.rate(target)
        if a and b:
            return Decimal(b) / Decimal(a)
        return None


Instruction:
Write a Python 3 script to
add paths for egg - info files for an external egg - base.

Response:
def _add_egg_info(self, cmd):
        """
        Add paths for egg-info files for an external egg-base.

        The egg-info files are written to egg-base. If egg-base is
        outside the current working directory, this method
        searchs the egg-base directory for files to include
        in the manifest. Uses distutils.filelist.findall (which is
        really the version monkeypatched in by setuptools/__init__.py)
        to perform the search.

        Since findall records relative paths, prefix the returned
        paths with cmd.egg_base, so add_default's include_pattern call
        (which is looking for the absolute cmd.egg_info) will match
        them.
        """
        if cmd.egg_base == os.curdir:
            # egg-info files were already added by something else
            return

        discovered = distutils.filelist.findall(cmd.egg_base)
        resolved = (os.path.join(cmd.egg_base, path) for path in discovered)
        self.filelist.allfiles.extend(resolved)


Instruction:
Can you tell what is the following Python 3 function doing
def write_delete_marker_file(directory):
    filepath = os.path.join(directory, PIP_DELETE_MARKER_FILENAME)
    with open(filepath, 'w') as marker_fp:
        marker_fp.write(DELETE_MARKER_MESSAGE)

Response: Writes the pip delete marker file into this directory.


Instruction:
Write a Python 3 script to
return True if we re running inside a virtualenv False otherwise.

Response:
def running_under_virtualenv():
    """
    Return True if we're running inside a virtualenv, False otherwise.

    """
    if hasattr(sys, 'real_prefix'):
        return True
    elif sys.prefix != getattr(sys, "base_prefix", sys.prefix):
        return True

    return False


Instruction:
Can you generate the documentation for the following Python 3 function
def __get_username():
    if WINDOWS:
        return getpass.getuser()
    import pwd
    return pwd.getpwuid(os.geteuid()).pw_name

Response: Returns the effective username of the current process.


Instruction:
Can you write a function in Python 3 where it
returns a distutils install scheme for the given distribution name.

Response:
def distutils_scheme(dist_name, user=False, home=None, root=None,
                     isolated=False):
    """
    Return a distutils install scheme
    """
    from distutils.dist import Distribution

    scheme = {}

    if isolated:
        extra_dist_args = {"script_args": ["--no-user-cfg"]}
    else:
        extra_dist_args = {}
    dist_args = {'name': dist_name}
    dist_args.update(extra_dist_args)

    d = Distribution(dist_args)
    d.parse_config_files()
    i = d.get_command_obj('install', create=True)
    # NOTE: setting user or home has the side-effect of creating the home dir
    # or user base for installations during finalize_options()
    # ideally, we'd prefer a scheme class that has no side-effects.
    i.user = user or i.user
    i.home = home or i.home
    i.root = root or i.root
    i.finalize_options()
    for key in SCHEME_KEYS:
        scheme[key] = getattr(i, 'install_' + key)

    if i.install_lib is not None:
        # install_lib takes precedence over purelib and platlib
        scheme.update(dict(purelib=i.install_lib, platlib=i.install_lib))

    if running_under_virtualenv():
        scheme['headers'] = os.path.join(
            sys.prefix,
            'include',
            'site',
            'python' + sys.version[:3],
            dist_name,
        )

        if root is not None:
            scheme["headers"] = os.path.join(
                root,
                os.path.abspath(scheme["headers"])[1:],
            )

    return scheme


Instruction:
Create a Python 3 function for
parsing the cache - control headers returning a dictionary with values for the different directives.

Response:
def parse_cache_control(self, headers):
        """
        Parse the cache control headers returning a dictionary with values
        for the different directives.
        """
        retval = {}

        cc_header = 'cache-control'
        if 'Cache-Control' in headers:
            cc_header = 'Cache-Control'

        if cc_header in headers:
            parts = headers[cc_header].split(',')
            parts_with_args = [
                tuple([x.strip().lower() for x in part.split("=", 1)])
                for part in parts if -1 != part.find("=")
            ]
            parts_wo_args = [
                (name.strip().lower(), 1)
                for name in parts if -1 == name.find("=")
            ]
            retval = dict(parts_with_args + parts_wo_args)
        return retval


Instruction:
Create a Python 3 function for
returning a cached response if it exists in the cache otherwise return False.

Response:
def cached_request(self, request):
        """
        Return a cached response if it exists in the cache, otherwise
        return False.
        """
        cache_url = self.cache_url(request.url)
        cc = self.parse_cache_control(request.headers)

        # non-caching states
        no_cache = True if 'no-cache' in cc else False
        if 'max-age' in cc and cc['max-age'] == 0:
            no_cache = True

        # Bail out if no-cache was set
        if no_cache:
            return False

        # It is in the cache, so lets see if it is going to be
        # fresh enough
        resp = self.serializer.loads(request, self.cache.get(cache_url))

        # Check to see if we have a cached object
        if not resp:
            return False

        # If we have a cached 301, return it immediately. We don't
        # need to test our response for other headers b/c it is
        # intrinsically "cacheable" as it is Permanent.
        # See:
        #   https://tools.ietf.org/html/rfc7231#section-6.4.2
        #
        # Client can try to refresh the value by repeating the request
        # with cache busting headers as usual (ie no-cache).
        if resp.status == 301:
            return resp

        headers = CaseInsensitiveDict(resp.headers)
        if not headers or 'date' not in headers:
            # With date or etag, the cached response can never be used
            # and should be deleted.
            if 'etag' not in headers:
                self.cache.delete(cache_url)
            return False

        now = time.time()
        date = calendar.timegm(
            parsedate_tz(headers['date'])
        )
        current_age = max(0, now - date)

        # TODO: There is an assumption that the result will be a
        #       urllib3 response object. This may not be best since we
        #       could probably avoid instantiating or constructing the
        #       response until we know we need it.
        resp_cc = self.parse_cache_control(headers)

        # determine freshness
        freshness_lifetime = 0

        # Check the max-age pragma in the cache control header
        if 'max-age' in resp_cc and resp_cc['max-age'].isdigit():
            freshness_lifetime = int(resp_cc['max-age'])

        # If there isn't a max-age, check for an expires header
        elif 'expires' in headers:
            expires = parsedate_tz(headers['expires'])
            if expires is not None:
                expire_time = calendar.timegm(expires) - date
                freshness_lifetime = max(0, expire_time)

        # determine if we are setting freshness limit in the req
        if 'max-age' in cc:
            try:
                freshness_lifetime = int(cc['max-age'])
            except ValueError:
                freshness_lifetime = 0

        if 'min-fresh' in cc:
            try:
                min_fresh = int(cc['min-fresh'])
            except ValueError:
                min_fresh = 0
            # adjust our current age by our min fresh
            current_age += min_fresh

        # see how fresh we actually are
        fresh = (freshness_lifetime > current_age)

        if fresh:
            return resp

        # we're not fresh. If we don't have an Etag, clear it out
        if 'etag' not in headers:
            self.cache.delete(cache_url)

        # return the original handler
        return False


Instruction:
Can you generate a brief explanation for the following Python 3 code
def cache_response(self, request, response, body=None):
        # From httplib2: Don't cache 206's since we aren't going to
        #                handle byte range requests
        if response.status not in [200, 203, 300, 301]:
            return

        response_headers = CaseInsensitiveDict(response.headers)

        cc_req = self.parse_cache_control(request.headers)
        cc = self.parse_cache_control(response_headers)

        cache_url = self.cache_url(request.url)

        # Delete it from the cache if we happen to have it stored there
        no_store = cc.get('no-store') or cc_req.get('no-store')
        if no_store and self.cache.get(cache_url):
            self.cache.delete(cache_url)

        # If we've been given an etag, then keep the response
        if self.cache_etags and 'etag' in response_headers:
            self.cache.set(
                cache_url,
                self.serializer.dumps(request, response, body=body),
            )

        # Add to the cache any 301s. We do this before looking that
        # the Date headers.
        elif response.status == 301:
            self.cache.set(
                cache_url,
                self.serializer.dumps(request, response)
            )

        # Add to the cache if the response headers demand it. If there
        # is no date header then we can't do anything about expiring
        # the cache.
        elif 'date' in response_headers:
            # cache when there is a max-age > 0
            if cc and cc.get('max-age'):
                if int(cc['max-age']) > 0:
                    self.cache.set(
                        cache_url,
                        self.serializer.dumps(request, response, body=body),
                    )

            # If the request can expire, it means we should cache it
            # in the meantime.
            elif 'expires' in response_headers:
                if response_headers['expires']:
                    self.cache.set(
                        cache_url,
                        self.serializer.dumps(request, response, body=body),
                    )

Response:
Algorithm for caching requests.

        This assumes a requests Response object.


Instruction:
Create a Python 3 function for
updating the zipimporter cache data for a given normalized path.

Response:
def _update_zipimporter_cache(normalized_path, cache, updater=None):
    """
    Update zipimporter cache data for a given normalized path.

    Any sub-path entries are processed as well, i.e. those corresponding to zip
    archives embedded in other zip archives.

    Given updater is a callable taking a cache entry key and the original entry
    (after already removing the entry from the cache), and expected to update
    the entry and possibly return a new one to be inserted in its place.
    Returning None indicates that the entry should not be replaced with a new
    one. If no updater is given, the cache entries are simply removed without
    any additional processing, the same as if the updater simply returned None.

    """
    for p in _collect_zipimporter_cache_entries(normalized_path, cache):
        # N.B. pypy's custom zipimport._zip_directory_cache implementation does
        # not support the complete dict interface:
        # * Does not support item assignment, thus not allowing this function
        #    to be used only for removing existing cache entries.
        #  * Does not support the dict.pop() method, forcing us to use the
        #    get/del patterns instead. For more detailed information see the
        #    following links:
        #      https://bitbucket.org/pypa/setuptools/issue/202/more-robust-zipimporter-cache-invalidation#comment-10495960
        #      https://bitbucket.org/pypy/pypy/src/dd07756a34a41f674c0cacfbc8ae1d4cc9ea2ae4/pypy/module/zipimport/interp_zipimport.py#cl-99
        old_entry = cache[p]
        del cache[p]
        new_entry = updater and updater(p, old_entry)
        if new_entry is not None:
            cache[p] = new_entry


Instruction:
Can you generate a brief explanation for the following Python 3 code
def get_win_launcher(type):
    launcher_fn = '%s.exe' % type
    if platform.machine().lower() == 'arm':
        launcher_fn = launcher_fn.replace(".", "-arm.")
    if is_64bit():
        launcher_fn = launcher_fn.replace(".", "-64.")
    else:
        launcher_fn = launcher_fn.replace(".", "-32.")
    return resource_string('setuptools', launcher_fn)

Response: Load the Windows launcher suitable for launching a script.


Instruction:
How would you implement a function in Python 3 that
returns a pseudo - tempdir base in the install directory.

Response:
def pseudo_tempname(self):
        """Return a pseudo-tempname base in the install directory.
        This code is intentionally naive; if a malicious party can write to
        the target directory you're already in deep doodoo.
        """
        try:
            pid = os.getpid()
        except:
            pid = random.randint(0, maxsize)
        return os.path.join(self.install_dir, "test-easy-install-%s" % pid)


Instruction:
Can you generate the documentation for the following Python 3 function
def install_script(self, dist, script_name, script_text, dev_path=None):
        spec = str(dist.as_requirement())
        is_script = is_python_script(script_text, script_name)

        if is_script:
            script_text = (ScriptWriter.get_header(script_text) +
                           self._load_template(dev_path) % locals())
        self.write_script(script_name, _to_ascii(script_text), 'b')

Response: Generate a legacy script wrapper and install it


Instruction:
Write a Python 3 function that can
load the template file and return it as a string.

Response:
def _load_template(dev_path):
        """
        There are a couple of template scripts in the package. This
        function loads one of them and prepares it for use.
        """
        # See https://bitbucket.org/pypa/setuptools/issue/134 for info
        # on script file naming and downstream issues with SVR4
        name = 'script.tmpl'
        if dev_path:
            name = name.replace('.tmpl', ' (dev).tmpl')

        raw_bytes = resource_string('setuptools', name)
        return raw_bytes.decode('utf-8')


Instruction:
How would you explain what the following Python 3 function does
def install_site_py(self):

        if self.sitepy_installed:
            return  # already did it, or don't need to

        sitepy = os.path.join(self.install_dir, "site.py")
        source = resource_string("setuptools", "site-patch.py")
        current = ""

        if os.path.exists(sitepy):
            log.debug("Checking existing site.py in %s", self.install_dir)
            f = open(sitepy, 'rb')
            current = f.read()
            # we want str, not bytes
            if PY3:
                current = current.decode()

            f.close()
            if not current.startswith('def __boot():'):
                raise DistutilsError(
                    "%s is not a setuptools-generated site.py; please"
                    " remove it." % sitepy
                )

        if current != source:
            log.info("Creating %s", sitepy)
            if not self.dry_run:
                ensure_directory(sitepy)
                f = open(sitepy, 'wb')
                f.write(source)
                f.close()
            self.byte_compile([sitepy])

        self.sitepy_installed = True

Response: Install site. py if it doesn t exist.


Instruction:
Can you generate a brief explanation for the following Python 3 code
def save(self):
        if not self.dirty:
            return

        data = '\n'.join(map(self.make_relative, self.paths))
        if data:
            log.debug("Saving %s", self.filename)
            data = (
                "import sys; sys.__plen = len(sys.path)\n"
                "%s\n"
                "import sys; new=sys.path[sys.__plen:];"
                " del sys.path[sys.__plen:];"
                " p=getattr(sys,'__egginsert',0); sys.path[p:p]=new;"
                " sys.__egginsert = p+len(new)\n"
            ) % data

            if os.path.islink(self.filename):
                os.unlink(self.filename)
            f = open(self.filename, 'wt')
            f.write(data)
            f.close()

        elif os.path.exists(self.filename):
            log.debug("Deleting empty %s", self.filename)
            os.unlink(self.filename)

        self.dirty = False

Response: Write changed. pth file back to disk


Instruction:
How would you explain what the following Python 3 function does
def as_header(self):
        if not is_sh(self[0]):
            return super(JythonCommandSpec, self).as_header()

        if self.options:
            # Can't apply the workaround, leave it broken
            log.warn(
                "WARNING: Unable to adapt shebang line for Jython,"
                " the following script is NOT executable\n"
                "         see http://bugs.jython.org/issue1112 for"
                " more information.")
            return super(JythonCommandSpec, self).as_header()

        items = ['/usr/bin/env'] + self + list(self.options)
        return self._render(items)

Response: Returns the command line as a header string.


Instruction:
Can you generate the documentation for the following Python 3 function
def _adjust_header(type_, orig_header):
        pattern = 'pythonw.exe'
        repl = 'python.exe'
        if type_ == 'gui':
            pattern, repl = repl, pattern
        pattern_ob = re.compile(re.escape(pattern), re.IGNORECASE)
        new_header = pattern_ob.sub(string=orig_header, repl=repl)
        clean_header = new_header[2:-1].strip('"')
        if sys.platform == 'win32' and not os.path.exists(clean_header):
            # the adjusted version doesn't exist, so return the original
            return orig_header
        return new_header

Response: Adjust the header to include the version of the entry point.


Instruction:
Write a Python 3 script to
convert the value to an appropriate type.

Response:
def convert(self, value):
        """
        Convert values to an appropriate type. dicts, lists and tuples are
        replaced by their converting alternatives. Strings are checked to
        see if they have a conversion format and are converted if they do.
        """
        if not isinstance(value, ConvertingDict) and isinstance(value, dict):
            value = ConvertingDict(value)
            value.configurator = self
        elif not isinstance(value, ConvertingList) and isinstance(value, list):
            value = ConvertingList(value)
            value.configurator = self
        elif not isinstance(value, ConvertingTuple) and\
                 isinstance(value, tuple):
            value = ConvertingTuple(value)
            value.configurator = self
        elif isinstance(value, six.string_types):  # str for py3k
            m = self.CONVERT_PATTERN.match(value)
            if m:
                d = m.groupdict()
                prefix = d['prefix']
                converter = self.value_converters.get(prefix, None)
                if converter:
                    suffix = d['suffix']
                    converter = getattr(self, converter)
                    value = converter(suffix)
        return value


Instruction:
Write a Python 3 function that can
add filters to a filterer from a list of names.

Response:
def add_filters(self, filterer, filters):
        """Add filters to a filterer from a list of names."""
        for f in filters:
            try:
                filterer.addFilter(self.config['filters'][f])
            except StandardError as e:
                raise ValueError('Unable to add filter %r: %s' % (f, e))


Instruction:
How would you explain what the following Python 3 function does
def configure_handler(self, config):
        formatter = config.pop('formatter', None)
        if formatter:
            try:
                formatter = self.config['formatters'][formatter]
            except StandardError as e:
                raise ValueError('Unable to set formatter '
                                 '%r: %s' % (formatter, e))
        level = config.pop('level', None)
        filters = config.pop('filters', None)
        if '()' in config:
            c = config.pop('()')
            if not hasattr(c, '__call__') and hasattr(types, 'ClassType') and type(c) != types.ClassType:
                c = self.resolve(c)
            factory = c
        else:
            klass = self.resolve(config.pop('class'))
            # Special case for handler which refers to another handler
            if issubclass(klass, logging.handlers.MemoryHandler) and\
                'target' in config:
                try:
                    config['target'] = self.config['handlers'][config['target']]
                except StandardError as e:
                    raise ValueError('Unable to set target handler '
                                     '%r: %s' % (config['target'], e))
            elif issubclass(klass, logging.handlers.SMTPHandler) and\
                'mailhost' in config:
                config['mailhost'] = self.as_tuple(config['mailhost'])
            elif issubclass(klass, logging.handlers.SysLogHandler) and\
                'address' in config:
                config['address'] = self.as_tuple(config['address'])
            factory = klass
        kwargs = dict((k, config[k]) for k in config if valid_ident(k))
        try:
            result = factory(**kwargs)
        except TypeError as te:
            if "'stream'" not in str(te):
                raise
            # The argument name changed from strm to stream
            # Retry with old name.
            # This is so that code can be used with older Python versions
            #(e.g. by Django)
            kwargs['strm'] = kwargs.pop('stream')
            result = factory(**kwargs)
        if formatter:
            result.setFormatter(formatter)
        if level is not None:
            result.setLevel(_checkLevel(level))
        if filters:
            self.add_filters(result, filters)
        return result

Response: Configure a handler from a dictionary.


Instruction:
Create a Python 3 function to
add handlers to a logger from a list of names.

Response:
def add_handlers(self, logger, handlers):
        """Add handlers to a logger from a list of names."""
        for h in handlers:
            try:
                logger.addHandler(self.config['handlers'][h])
            except StandardError as e:
                raise ValueError('Unable to add handler %r: %s' % (h, e))


Instruction:
Can you create a Python 3 function that
performs configuration which is common to root and non - root loggers.

Response:
def common_logger_config(self, logger, config, incremental=False):
        """
        Perform configuration which is common to root and non-root loggers.
        """
        level = config.get('level', None)
        if level is not None:
            logger.setLevel(_checkLevel(level))
        if not incremental:
            # Remove any existing handlers
            for h in logger.handlers[:]:
                logger.removeHandler(h)
            handlers = config.get('handlers', None)
            if handlers:
                self.add_handlers(logger, handlers)
            filters = config.get('filters', None)
            if filters:
                self.add_filters(logger, filters)


Instruction:
Can you generate a brief explanation for the following Python 3 code
def from_envvar(self, variable_name, silent=False):
        rv = os.environ.get(variable_name)
        if not rv:
            if silent:
                return False
            raise RuntimeError('The environment variable %r is not set '
                               'and as such configuration could not be '
                               'loaded.  Set this variable and make it '
                               'point to a configuration file' %
                               variable_name)
        return self.from_pyfile(rv, silent=silent)

Response: Loads a configuration from an environment variable pointing to a configuration file.


Instruction:
Write a Python 3 script for
updating the values in the config from a Python file.

Response:
def from_pyfile(self, filename, silent=False):
        """Updates the values in the config from a Python file.  This function
        behaves as if the file was imported as module with the
        :meth:`from_object` function.

        :param filename: the filename of the config.  This can either be an
                         absolute filename or a filename relative to the
                         root path.
        :param silent: set to `True` if you want silent failure for missing
                       files.

        .. versionadded:: 0.7
           `silent` parameter.
        """
        filename = os.path.join(self.root_path, filename)
        d = imp.new_module('config')
        d.__file__ = filename
        try:
            with open(filename) as config_file:
                exec(compile(config_file.read(), filename, 'exec'), d.__dict__)
        except IOError as e:
            if silent and e.errno in (errno.ENOENT, errno.EISDIR):
                return False
            e.strerror = 'Unable to load configuration file (%s)' % e.strerror
            raise
        self.from_object(d)
        return True


Instruction:
Make a summary of the following Python 3 code
def from_object(self, obj):
        if isinstance(obj, string_types):
            obj = import_string(obj)
        for key in dir(obj):
            if key.isupper():
                self[key] = getattr(obj, key)

Response: Updates the values in the config object with the values from the given object.


Instruction:
Implement a function in Python 3 to
execute a file in Python 3.

Response:
def _execfile(filename, globals, locals=None):
    """
    Python 3 implementation of execfile.
    """
    mode = 'rb'
    with open(filename, mode) as stream:
        script = stream.read()
    # compile() function in Python 2.6 and 3.1 requires LF line endings.
    if sys.version_info[:2] < (2, 7) or sys.version_info[:2] >= (3, 0) and sys.version_info[:2] < (3, 2):
        script = script.replace(b'\r\n', b'\n')
        script = script.replace(b'\r', b'\n')
    if locals is None:
        locals = globals
    code = compile(script, filename, 'exec')
    exec(code, globals, locals)


Instruction:
Can you tell what is the following Python 3 function doing
def run_setup(setup_script, args):
    setup_dir = os.path.abspath(os.path.dirname(setup_script))
    with setup_context(setup_dir):
        try:
            sys.argv[:] = [setup_script]+list(args)
            sys.path.insert(0, setup_dir)
            # reset to include setup dir, w/clean callback list
            working_set.__init__()
            working_set.callbacks.append(lambda dist:dist.activate())
            def runner():
                ns = dict(__file__=setup_script, __name__='__main__')
                _execfile(setup_script, ns)
            DirectorySandbox(setup_dir).run(runner)
        except SystemExit as v:
            if v.args and v.args[0]:
                raise

Response: Run a distutils setup script sandboxed in its directory


Instruction:
Create a Python 3 function for
dumping a type and exception into a string.

Response:
def dump(cls, type, exc):
        """
        Always return a dumped (pickled) type and exc. If exc can't be pickled,
        wrap it in UnpickleableException first.
        """
        try:
            return pickle.dumps(type), pickle.dumps(exc)
        except Exception:
            return cls.dump(cls, cls(repr(exc)))


Instruction:
Can you generate a brief explanation for the following Python 3 code
def check_rev_options(self, rev, dest, rev_options):
        revisions = self.get_refs(dest)

        origin_rev = 'origin/%s' % rev
        if origin_rev in revisions:
            # remote branch
            return [revisions[origin_rev]]
        elif rev in revisions:
            # a local tag or branch name
            return [revisions[rev]]
        else:
            logger.warning(
                "Could not find a tag or branch '%s', assuming commit.", rev,
            )
            return rev_options

Response:
Check the revision options before checkout to compensate that tags
            and branches may need origin as a prefix.


Instruction:
Implement a Python 3 function for
returning the URL and revision of the current object.

Response:
def get_url_rev(self):
        """
        Prefixes stub URLs like 'user@hostname:user/repo.git' with 'ssh://'.
        That's required because although they use SSH they sometimes doesn't
        work with a ssh:// scheme (e.g. Github). But we need a scheme for
        parsing. Hence we remove it again afterwards and return it as a stub.
        """
        if '://' not in self.url:
            assert 'file:' not in self.url
            self.url = self.url.replace('git+', 'git+ssh://')
            url, rev = super(Git, self).get_url_rev()
            url = url.replace('ssh://', '')
        else:
            url, rev = super(Git, self).get_url_rev()

        return url, rev


Instruction:
Explain what the following Python 3 code does
def is_important_traceback(self, important_module, tb):
        while tb is not None:
            if self.is_important_frame(important_module, tb):
                return True
            tb = tb.tb_next
        return False

Response: Checks if a traceback is an important module.


Instruction:
Implement a Python 3 function for
getting an item or attribute of an object but prefer the item.

Response:
def getitem(self, obj, argument):
        """Get an item or attribute of an object but prefer the item."""
        try:
            return obj[argument]
        except (TypeError, LookupError):
            if isinstance(argument, string_types):
                try:
                    attr = str(argument)
                except Exception:
                    pass
                else:
                    try:
                        return getattr(obj, attr)
                    except AttributeError:
                        pass
            return self.undefined(obj=obj, name=argument)


Instruction:
Can you create a Python 3 function that
compiles all the templates in the target directory and store them in the zip.

Response:
def compile_templates(self, target, extensions=None, filter_func=None,
                          zip='deflated', log_function=None,
                          ignore_errors=True, py_compile=False):
        """Finds all the templates the loader can find, compiles them
        and stores them in `target`.  If `zip` is `None`, instead of in a
        zipfile, the templates will be will be stored in a directory.
        By default a deflate zip algorithm is used, to switch to
        the stored algorithm, `zip` can be set to ``'stored'``.

        `extensions` and `filter_func` are passed to :meth:`list_templates`.
        Each template returned will be compiled to the target folder or
        zipfile.

        By default template compilation errors are ignored.  In case a
        log function is provided, errors are logged.  If you want template
        syntax errors to abort the compilation you can set `ignore_errors`
        to `False` and you will get an exception on syntax errors.

        If `py_compile` is set to `True` .pyc files will be written to the
        target instead of standard .py files.  This flag does not do anything
        on pypy and Python 3 where pyc files are not picked up by itself and
        don't give much benefit.

        .. versionadded:: 2.4
        """
        from jinja2.loaders import ModuleLoader

        if log_function is None:
            log_function = lambda x: None

        if py_compile:
            if not PY2 or PYPY:
                from warnings import warn
                warn(Warning('py_compile has no effect on pypy or Python 3'))
                py_compile = False
            else:
                import imp, marshal
                py_header = imp.get_magic() + \
                    u'\xff\xff\xff\xff'.encode('iso-8859-15')

                # Python 3.3 added a source filesize to the header
                if sys.version_info >= (3, 3):
                    py_header += u'\x00\x00\x00\x00'.encode('iso-8859-15')

        def write_file(filename, data, mode):
            if zip:
                info = ZipInfo(filename)
                info.external_attr = 0o755 << 16
                zip_file.writestr(info, data)
            else:
                f = open(os.path.join(target, filename), mode)
                try:
                    f.write(data)
                finally:
                    f.close()

        if zip is not None:
            from zipfile import ZipFile, ZipInfo, ZIP_DEFLATED, ZIP_STORED
            zip_file = ZipFile(target, 'w', dict(deflated=ZIP_DEFLATED,
                                                 stored=ZIP_STORED)[zip])
            log_function('Compiling into Zip archive "%s"' % target)
        else:
            if not os.path.isdir(target):
                os.makedirs(target)
            log_function('Compiling into folder "%s"' % target)

        try:
            for name in self.list_templates(extensions, filter_func):
                source, filename, _ = self.loader.get_source(self, name)
                try:
                    code = self.compile(source, name, filename, True, True)
                except TemplateSyntaxError as e:
                    if not ignore_errors:
                        raise
                    log_function('Could not compile "%s": %s' % (name, e))
                    continue

                filename = ModuleLoader.get_module_filename(name)

                if py_compile:
                    c = self._compile(code, encode_filename(filename))
                    write_file(filename + 'c', py_header +
                               marshal.dumps(c), 'wb')
                    log_function('Byte-compiled "%s" as %s' %
                                 (name, filename + 'c'))
                else:
                    write_file(filename, code, 'w')
                    log_function('Compiled "%s" as %s' % (name, filename))
        finally:
            if zip:
                zip_file.close()

        log_function('Finished compiling templates')


Instruction:
Create a Python 3 function for
returning a list of templates for this environment.

Response:
def list_templates(self, extensions=None, filter_func=None):
        """Returns a list of templates for this environment.  This requires
        that the loader supports the loader's
        :meth:`~BaseLoader.list_templates` method.

        If there are other files in the template folder besides the
        actual templates, the returned list can be filtered.  There are two
        ways: either `extensions` is set to a list of file extensions for
        templates, or a `filter_func` can be provided which is a callable that
        is passed a template name and should return `True` if it should end up
        in the result list.

        If the loader does not support that, a :exc:`TypeError` is raised.

        .. versionadded:: 2.4
        """
        x = self.loader.list_templates()
        if extensions is not None:
            if filter_func is not None:
                raise TypeError('either extensions or filter_func '
                                'can be passed, but not both')
            filter_func = lambda x: '.' in x and \
                                    x.rsplit('.', 1)[1] in extensions
        if filter_func is not None:
            x = ifilter(filter_func, x)
        return x


Instruction:
How would you code a function in Python 3 to
determine the default cache location for the current user.

Response:
def get_default_cache():
    """Determine the default cache location

    This returns the ``PYTHON_EGG_CACHE`` environment variable, if set.
    Otherwise, on Windows, it returns a "Python-Eggs" subdirectory of the
    "Application Data" directory.  On all other systems, it's "~/.python-eggs".
    """
    try:
        return os.environ['PYTHON_EGG_CACHE']
    except KeyError:
        pass

    if os.name!='nt':
        return os.path.expanduser('~/.python-eggs')

    # XXX this may be locale-specific!
    app_data = 'Application Data'
    app_homes = [
        # best option, should be locale-safe
        (('APPDATA',), None),
        (('USERPROFILE',), app_data),
        (('HOMEDRIVE','HOMEPATH'), app_data),
        (('HOMEPATH',), app_data),
        (('HOME',), None),
        # 95/98/ME
        (('WINDIR',), app_data),
    ]

    for keys, subdir in app_homes:
        dirname = ''
        for key in keys:
            if key in os.environ:
                dirname = os.path.join(dirname, os.environ[key])
            else:
                break
        else:
            if subdir:
                dirname = os.path.join(dirname, subdir)
            return os.path.join(dirname, 'Python-Eggs')
    else:
        raise RuntimeError(
            "Please set the PYTHON_EGG_CACHE enviroment variable"
        )


Instruction:
Write a Python 3 script to
find eggs in zip files.

Response:
def find_eggs_in_zip(importer, path_item, only=False):
    """
    Find eggs in zip files; possibly multiple nested eggs.
    """
    if importer.archive.endswith('.whl'):
        # wheels are not supported with this finder
        # they don't have PKG-INFO metadata, and won't ever contain eggs
        return
    metadata = EggMetadata(importer)
    if metadata.has_metadata('PKG-INFO'):
        yield Distribution.from_filename(path_item, metadata=metadata)
    if only:
        # don't yield nested distros
        return
    for subitem in metadata.resource_listdir('/'):
        if subitem.endswith('.egg'):
            subpath = os.path.join(path_item, subitem)
            for dist in find_eggs_in_zip(zipimport.zipimporter(subpath), subpath):
                yield dist


Instruction:
Can you generate a brief explanation for the following Python 3 code
def find_on_path(importer, path_item, only=False):
    path_item = _normalize_cached(path_item)

    if os.path.isdir(path_item) and os.access(path_item, os.R_OK):
        if path_item.lower().endswith('.egg'):
            # unpacked egg
            yield Distribution.from_filename(
                path_item, metadata=PathMetadata(
                    path_item, os.path.join(path_item,'EGG-INFO')
                )
            )
        else:
            # scan for .egg and .egg-info in directory
            for entry in os.listdir(path_item):
                lower = entry.lower()
                if lower.endswith('.egg-info') or lower.endswith('.dist-info'):
                    fullpath = os.path.join(path_item, entry)
                    if os.path.isdir(fullpath):
                        # egg-info directory, allow getting metadata
                        metadata = PathMetadata(path_item, fullpath)
                    else:
                        metadata = FileMetadata(fullpath)
                    yield Distribution.from_location(
                        path_item, entry, metadata, precedence=DEVELOP_DIST
                    )
                elif not only and lower.endswith('.egg'):
                    dists = find_distributions(os.path.join(path_item, entry))
                    for dist in dists:
                        yield dist
                elif not only and lower.endswith('.egg-link'):
                    with open(os.path.join(path_item, entry)) as entry_file:
                        entry_lines = entry_file.readlines()
                    for line in entry_lines:
                        if not line.strip():
                            continue
                        path = os.path.join(path_item, line.rstrip())
                        dists = find_distributions(path)
                        for item in dists:
                            yield item
                        break

Response: Yields distributions accessible on a sys. path directory.


Instruction:
Can you implement a function in Python 3 that
declares that package packageName is a namespace package.

Response:
def declare_namespace(packageName):
    """Declare that package 'packageName' is a namespace package"""

    imp.acquire_lock()
    try:
        if packageName in _namespace_packages:
            return

        path, parent = sys.path, None
        if '.' in packageName:
            parent = '.'.join(packageName.split('.')[:-1])
            declare_namespace(parent)
            if parent not in _namespace_packages:
                __import__(parent)
            try:
                path = sys.modules[parent].__path__
            except AttributeError:
                raise TypeError("Not a package:", parent)

        # Track what packages are namespaces, so when new path items are added,
        # they can be updated
        _namespace_packages.setdefault(parent,[]).append(packageName)
        _namespace_packages.setdefault(packageName,[])

        for path_item in path:
            # Ensure all the parent's path items are reflected in the child,
            # if they apply
            _handle_ns(packageName, path_item)

    finally:
        imp.release_lock()


Instruction:
Write a Python 3 function that can
yield non - empty lines of a string or sequence of lines

Response:
def yield_lines(strs):
    """Yield non-empty/non-comment lines of a string or sequence"""
    if isinstance(strs, string_types):
        for s in strs.splitlines():
            s = s.strip()
            # skip blank lines/comments
            if s and not s.startswith('#'):
                yield s
    else:
        for ss in strs:
            for s in yield_lines(ss):
                yield s


Instruction:
Write a Python 3 script for
getting an mro for a class or a type

Response:
def _get_mro(cls):
    """Get an mro for a type or classic class"""
    if not isinstance(cls, type):
        class cls(cls, object): pass
        return cls.__mro__[1:]
    return cls.__mro__


Instruction:
Implement a function in Python 3 to
return an adapter factory for an object from the registry

Response:
def _find_adapter(registry, ob):
    """Return an adapter factory for `ob` from `registry`"""
    for t in _get_mro(getattr(ob, '__class__', type(ob))):
        if t in registry:
            return registry[t]


Instruction:
Explain what the following Python 3 code does
def ensure_directory(path):
    dirname = os.path.dirname(path)
    if not os.path.isdir(dirname):
        os.makedirs(dirname)

Response: Ensure that the parent directory of path exists


Instruction:
Can you tell what is the following Python 3 function doing
def iter_entry_points(self, group, name=None):
        for dist in self:
            entries = dist.get_entry_map(group)
            if name is None:
                for ep in entries.values():
                    yield ep
            elif name in entries:
                yield entries[name]

Response: Yields all entry points in a group matching name.


Instruction:
How would you code a function in Python 3 to
subscribe to all distributions including existing ones.

Response:
def subscribe(self, callback):
        """Invoke `callback` for all distributions (including existing ones)"""
        if callback in self.callbacks:
            return
        self.callbacks.append(callback)
        for dist in self:
            callback(dist)


Instruction:
Can you generate a brief explanation for the following Python 3 code
def can_add(self, dist):
        return (self.python is None or dist.py_version is None
            or dist.py_version==self.python) \
            and compatible_platforms(dist.platform, self.platform)

Response: Is distribution dist acceptable for this environment?


Instruction:
Create a Python 3 function to
find the best matching distribution that matches the given requirement and usable on the given working_set.

Response:
def best_match(self, req, working_set, installer=None):
        """Find distribution best matching `req` and usable on `working_set`

        This calls the ``find(req)`` method of the `working_set` to see if a
        suitable distribution is already active.  (This may raise
        ``VersionConflict`` if an unsuitable version of the project is already
        active in the specified `working_set`.)  If a suitable distribution
        isn't active, this method returns the newest distribution in the
        environment that meets the ``Requirement`` in `req`.  If no suitable
        distribution is found, and `installer` is supplied, then the result of
        calling the environment's ``obtain(req, installer)`` method will be
        returned.
        """
        dist = working_set.find(req)
        if dist is not None:
            return dist
        for dist in self[req.key]:
            if dist in req:
                return dist
        # try to download/install
        return self.obtain(req, installer)


Instruction:
Can you create a Python 3 function that
gives an error message for problems extracting file(s

Response:
def extraction_error(self):
        """Give an error message for problems extracting file(s)"""

        old_exc = sys.exc_info()[1]
        cache_path = self.extraction_path or get_default_cache()

        err = ExtractionError("""Can't extract file(s) to egg cache

The following error occurred while trying to extract file(s) to the Python egg
cache:

  %s

The Python egg cache directory is currently set to:

  %s

Perhaps your account does not have write access to this directory?  You can
change the cache directory by setting the PYTHON_EGG_CACHE environment
variable to point to an accessible directory.
""" % (old_exc, cache_path)
        )
        err.manager = self
        err.cache_path = cache_path
        err.original_error = old_exc
        raise err


Instruction:
Given the following Python 3 function, write the documentation
def is_invalid_marker(cls, text):
        try:
            cls.evaluate_marker(text)
        except SyntaxError as e:
            return cls.normalize_exception(e)
        return False

Response:
Validate text as a PEP 426 environment marker ; return an exception
        if invalid or False otherwise.


Instruction:
How would you code a function in Python 3 to
give an exception from a marker evaluation normalize the error message and return the exception.

Response:
def normalize_exception(exc):
        """
        Given a SyntaxError from a marker evaluation, normalize the error
        message:
         - Remove indications of filename and line number.
         - Replace platform-specific error messages with standard error
           messages.
        """
        subs = {
            'unexpected EOF while parsing': 'invalid syntax',
            'parenthesis is never closed': 'invalid syntax',
        }
        exc.filename = None
        exc.lineno = None
        exc.msg = subs.get(exc.msg, exc.msg)
        return exc


Instruction:
Here you have a function in Python 3, explain what it does
def evaluate_marker(cls, text, extra=None):
        return cls.interpret(parser.expr(text).totuple(1)[1])

Response: Evaluate a PEP 426 environment marker on CPython 2. 4 +.


Instruction:
Create a Python 3 function for
evaluating a PEP 426 environment marker using markerlib.

Response:
def _markerlib_evaluate(cls, text):
        """
        Evaluate a PEP 426 environment marker using markerlib.
        Return a boolean indicating the marker result in this environment.
        Raise SyntaxError if marker is invalid.
        """
        from pip._vendor import _markerlib
        # markerlib implements Metadata 1.2 (PEP 345) environment markers.
        # Translate the variables to Metadata 2.0 (PEP 426).
        env = _markerlib.default_environment()
        for key in env.keys():
            new_key = key.replace('.', '_')
            env[new_key] = env.pop(key)
        try:
            result = _markerlib.interpret(text, env)
        except NameError as e:
            raise SyntaxError(e.args[0])
        return result


Instruction:
Can you write a function in Python 3 where it
inserts self. location in path before its nearest parent directory.

Response:
def insert_on(self, path, loc = None):
        """Insert self.location in path before its nearest parent directory"""

        loc = loc or self.location
        if not loc:
            return

        nloc = _normalize_cached(loc)
        bdir = os.path.dirname(nloc)
        npath= [(p and _normalize_cached(p) or p) for p in path]

        for p, item in enumerate(npath):
            if item == nloc:
                break
            elif item == bdir and self.precedence == EGG_DIST:
                # if it's an .egg, give it precedence over its directory
                if path is sys.path:
                    self.check_version_conflict()
                path.insert(p, loc)
                npath.insert(p, nloc)
                break
        else:
            if path is sys.path:
                self.check_version_conflict()
            path.append(loc)
            return

        # p is the spot where we found or inserted loc; now remove duplicates
        while True:
            try:
                np = npath.index(nloc, p+1)
            except ValueError:
                break
            else:
                del npath[np], path[np]
                # ha!
                p = np

        return


Instruction:
Write a Python 3 script to
convert a string containing a requirement into a tuple of the distvers and mark.

Response:
def _preparse_requirement(self, requires_dist):
        """Convert 'Foobar (1); baz' to ('Foobar ==1', 'baz')
        Split environment marker, add == prefix to version specifiers as
        necessary, and remove parenthesis.
        """
        parts = requires_dist.split(';', 1) + ['']
        distvers = parts[0].strip()
        mark = parts[1].strip()
        distvers = re.sub(self.EQEQ, r"\1==\2\3", distvers)
        distvers = distvers.replace('(', '').replace(')', '')
        return (distvers, mark)


Instruction:
Can you create a Python 3 function that
formats the log record with the current indentation level.

Response:
def format(self, record):
        """
        Calls the standard formatter, but will indent all of the log messages
        by our current indentation level.
        """
        formatted = logging.Formatter.format(self, record)
        formatted = "".join([
            (" " * get_indentation()) + line
            for line in formatted.splitlines(True)
        ])
        return formatted


Instruction:
Can you tell what is the following Python 3 function doing
def format_currency(number, currency, format=None,
                    locale=LC_NUMERIC, currency_digits=True,
                    format_type='standard', decimal_quantization=True):

    """Return formatted currency value.

    >>> format_currency(1099.98, 'USD', locale='en_US')
    u'$1,099.98'
    >>> format_currency(1099.98, 'USD', locale='es_CO')
    u'US$\\xa01.099,98'
    >>> format_currency(1099.98, 'EUR', locale='de_DE')
    u'1.099,98\\xa0\\u20ac'

    The format can also be specified explicitly.  The currency is
    placed with the '¤' sign.  As the sign gets repeated the format
    expands (¤ being the symbol, ¤¤ is the currency abbreviation and
    ¤¤¤ is the full name of the currency):

    >>> format_currency(1099.98, 'EUR', u'\xa4\xa4 #,##0.00', locale='en_US')
    u'EUR 1,099.98'
    >>> format_currency(1099.98, 'EUR', u'#,##0.00 \xa4\xa4\xa4',
    ...                 locale='en_US')
    u'1,099.98 euros'

    Currencies usually have a specific number of decimal digits. This function
    favours that information over the given format:

    >>> format_currency(1099.98, 'JPY', locale='en_US')
    u'\\xa51,100'
    >>> format_currency(1099.98, 'COP', u'#,##0.00', locale='es_ES')
    u'1.100'

    However, the number of decimal digits can be overriden from the currency
    information, by setting the last parameter to ``False``:

    >>> format_currency(1099.98, 'JPY', locale='en_US', currency_digits=False)
    u'\\xa51,099.98'
    >>> format_currency(1099.98, 'COP', u'#,##0.00', locale='es_ES',
    ...                 currency_digits=False)
    u'1.099,98'

    If a format is not specified the type of currency format to use
    from the locale can be specified:

    >>> format_currency(1099.98, 'EUR', locale='en_US', format_type='standard')
    u'\\u20ac1,099.98'

    When the given currency format type is not available, an exception is
    raised:

    >>> format_currency('1099.98', 'EUR', locale='root', format_type='unknown')
    Traceback (most recent call last):
        ...
    UnknownCurrencyFormatError: "'unknown' is not a known currency format type"

    By default the locale is allowed to truncate and round a high-precision
    number by forcing its format pattern onto the decimal part. You can bypass
    this behavior with the `decimal_quantization` parameter:

    >>> format_currency(1099.9876, 'USD', locale='en_US')
    u'$1,099.99'
    >>> format_currency(1099.9876, 'USD', locale='en_US',
    ...                 decimal_quantization=False)
    u'$1,099.9876'

    :param number: the number to format
    :param currency: the currency code
    :param format: the format string to use
    :param locale: the `Locale` object or locale identifier
    :param currency_digits: use the currency's natural number of decimal digits
    :param format_type: the currency format type to use
    :param decimal_quantization: Truncate and round high-precision numbers to
                                 the format pattern. Defaults to `True`.
    """

    locale = Locale.parse(locale)
    if format:
        pattern = parse_pattern(format)
    else:
        try:
            p = locale.currency_formats[format_type]
            pattern = NumberPattern(
                p.pattern, p.prefix, p.suffix, p.grouping, p.int_prec,
                p.frac_prec, p.exp_prec, p.exp_plus)

        except KeyError:
            raise UnknownCurrencyFormatError(
                "%r is not a known currency format type" % format_type)
    return pattern.apply(
        number, locale, currency=currency, currency_digits=currency_digits,
        decimal_quantization=decimal_quantization)

Response: Return formatted currency value.


Instruction:
Here you have a function in Python 3, explain what it does
def parse_pattern(pattern):
    if isinstance(pattern, NumberPattern):
        return pattern

    def _match_number(pattern):
        rv = number_re.search(pattern)
        if rv is None:
            raise ValueError('Invalid number pattern %r' % pattern)
        return rv.groups()

    pos_pattern = pattern

    # Do we have a negative subpattern?
    if ';' in pattern:
        pos_pattern, neg_pattern = pattern.split(';', 1)
        pos_prefix, number, pos_suffix = _match_number(pos_pattern)
        neg_prefix, _, neg_suffix = _match_number(neg_pattern)
    else:
        pos_prefix, number, pos_suffix = _match_number(pos_pattern)
        neg_prefix = '-' + pos_prefix
        neg_suffix = pos_suffix
    if 'E' in number:
        number, exp = number.split('E', 1)
    else:
        exp = None
    if '@' in number:
        if '.' in number and '0' in number:
            raise ValueError('Significant digit patterns can not contain '
                             '"@" or "0"')
    if '.' in number:
        integer, fraction = number.rsplit('.', 1)
    else:
        integer = number
        fraction = ''

    def parse_precision(p):
        """Calculate the min and max allowed digits"""
        min = max = 0
        for c in p:
            if c in '@0':
                min += 1
                max += 1
            elif c == '#':
                max += 1
            elif c == ',':
                continue
            else:
                break
        return min, max

    int_prec = parse_precision(integer)
    frac_prec = parse_precision(fraction)
    if exp:
        exp_plus = exp.startswith('+')
        exp = exp.lstrip('+')
        exp_prec = parse_precision(exp)
    else:
        exp_plus = None
        exp_prec = None
    grouping = babel.numbers.parse_grouping(integer)
    return NumberPattern(pattern, (pos_prefix, neg_prefix),
                         (pos_suffix, neg_suffix), grouping,
                         int_prec, frac_prec,
                         exp_prec, exp_plus)

Response: Parse a number format pattern and return a list of all possible number patterns.


Instruction:
Given the following Python 3 function, write the documentation
def get_decimal_quantum(precision):
    assert isinstance(precision, (int, decimal.Decimal))
    return decimal.Decimal(10) ** (-precision)

Response: Return minimal quantum of a number as defined by precision.


Instruction:
Here you have a function in Python 3, explain what it does
def get_decimal_precision(number):
    # Copied from: https://github.com/mahmoud/boltons/pull/59
    assert isinstance(number, decimal.Decimal)
    decimal_tuple = number.normalize().as_tuple()
    if decimal_tuple.exponent >= 0:
        return 0
    return abs(decimal_tuple.exponent)

Response: Returns the maximum precision of a decimal instance.


Instruction:
Can you generate a brief explanation for the following Python 3 code
def apply(
            self, value, locale, currency=None, currency_digits=True,
            decimal_quantization=True):
        """Renders into a string a number following the defined pattern.
        Forced decimal quantization is active by default so we'll produce a
        number string that is strictly following CLDR pattern definitions.
        """
        if not isinstance(value, decimal.Decimal):
            value = decimal.Decimal(str(value))

        value = value.scaleb(self.scale)

        # Separate the absolute value from its sign.
        is_negative = int(value.is_signed())
        value = abs(value).normalize()

        # Prepare scientific notation metadata.
        if self.exp_prec:
            value, exp, exp_sign = self.scientific_notation_elements(
                value, locale)

        # Adjust the precision of the fractionnal part and force it to the
        # currency's if neccessary.
        frac_prec = self.frac_prec
        if currency and currency_digits:
            frac_prec = (babel.numbers.get_currency_precision(currency), ) * 2

        # Bump decimal precision to the natural precision of the number if it
        # exceeds the one we're about to use. This adaptative precision is only
        # triggered if the decimal quantization is disabled or if a scientific
        # notation pattern has a missing mandatory fractional part (as in the
        # default '#E0' pattern). This special case has been extensively
        # discussed at
        # https://github.com/python-babel/babel/pull/494#issuecomment-307649969
        if not decimal_quantization or (self.exp_prec and frac_prec == (0, 0)):
            frac_prec = (frac_prec[0], max([frac_prec[1],
                                            get_decimal_precision(value)]))

        # Render scientific notation.
        if self.exp_prec:
            number = ''.join([
                self._quantize_value(value, locale, frac_prec),
                babel.numbers.get_exponential_symbol(locale),
                exp_sign,
                self._format_int(
                    str(exp), self.exp_prec[0], self.exp_prec[1], locale)])

        # Is it a siginificant digits pattern?
        elif '@' in self.pattern:
            text = self._format_significant(value,
                                            self.int_prec[0],
                                            self.int_prec[1])
            a, sep, b = text.partition(".")
            number = self._format_int(a, 0, 1000, locale)
            if sep:
                number += babel.numbers.get_decimal_symbol(locale) + b

        # A normal number pattern.
        else:
            number = self._quantize_value(value, locale, frac_prec)

        retval = ''.join([
            self.prefix[is_negative],
            number,
            self.suffix[is_negative]])

        if u'¤' in retval:
            retval = retval.replace(u'¤¤¤',
                                    babel.numbers.get_currency_name(
                                        currency, value, locale))
            retval = retval.replace(u'¤¤', currency.upper())
            retval = retval.replace(u'¤', babel.numbers.get_currency_symbol(
                currency, locale))

        return retval

Response: Applies the values to the CLDR number metadata.


Instruction:
Write a Python 3 script to
return normalized scientific notation components of a value.

Response:
def scientific_notation_elements(self, value, locale):
        """ Returns normalized scientific notation components of a value."""
        # Normalize value to only have one lead digit.
        exp = value.adjusted()
        value = value * get_decimal_quantum(exp)
        assert value.adjusted() == 0

        # Shift exponent and value by the minimum number of leading digits
        # imposed by the rendering pattern. And always make that number
        # greater or equal to 1.
        lead_shift = max([1, min(self.int_prec)]) - 1
        exp = exp - lead_shift
        value = value * get_decimal_quantum(-lead_shift)

        # Get exponent sign symbol.
        exp_sign = ''
        if exp < 0:
            exp_sign = babel.numbers.get_minus_sign_symbol(locale)
        elif self.exp_plus:
            exp_sign = babel.numbers.get_plus_sign_symbol(locale)

        # Normalize exponent value now that we have the sign.
        exp = abs(exp)

        return value, exp, exp_sign


Instruction:
Implement a function in Python 3 to
patch distutils. msvc9compiler to use the standalone compiler build for Python.

Response:
def patch_for_specialized_compiler():
    """
    Patch functions in distutils.msvc9compiler to use the standalone compiler
    build for Python (Windows only). Fall back to original behavior when the
    standalone compiler is not available.
    """
    if 'distutils' not in globals():
        # The module isn't available to be patched
        return

    if unpatched:
        # Already patched
        return

    unpatched.update(vars(distutils.msvc9compiler))

    distutils.msvc9compiler.find_vcvarsall = find_vcvarsall
    distutils.msvc9compiler.query_vcvarsall = query_vcvarsall


Instruction:
Explain what the following Python 3 code does
def total_seconds(td):
    if hasattr(td, 'total_seconds'):
        return td.total_seconds()

    ms = td.microseconds
    secs = (td.seconds + td.days * 24 * 3600)
    return (ms + secs * 10**6) / 10**6

Response: Python 2. 6 compatability


Instruction:
Explain what the following Python 3 code does
def parse_requirements(strs):
    # create a steppable iterator, so we can handle \-continuations
    lines = iter(yield_lines(strs))

    def scan_list(ITEM, TERMINATOR, line, p, groups, item_name):

        items = []

        while not TERMINATOR(line, p):
            if CONTINUE(line, p):
                try:
                    line = next(lines)
                    p = 0
                except StopIteration:
                    msg = "\\ must not appear on the last nonblank line"
                    raise RequirementParseError(msg)

            match = ITEM(line, p)
            if not match:
                msg = "Expected " + item_name + " in"
                raise RequirementParseError(msg, line, "at", line[p:])

            items.append(match.group(*groups))
            p = match.end()

            match = COMMA(line, p)
            if match:
                # skip the comma
                p = match.end()
            elif not TERMINATOR(line, p):
                msg = "Expected ',' or end-of-list in"
                raise RequirementParseError(msg, line, "at", line[p:])

        match = TERMINATOR(line, p)
        # skip the terminator, if any
        if match:
            p = match.end()
        return line, p, items

    for line in lines:
        match = DISTRO(line)
        if not match:
            raise RequirementParseError("Missing distribution spec", line)
        project_name = match.group(1)
        p = match.end()
        extras = []

        match = OBRACKET(line, p)
        if match:
            p = match.end()
            line, p, extras = scan_list(
                DISTRO, CBRACKET, line, p, (1,), "'extra' name"
            )

        line, p, specs = scan_list(VERSION, LINE_END, line, p, (1, 2),
            "version spec")
        specs = [(op, val) for op, val in specs]
        yield Requirement(project_name, specs, extras)

Response: Parse a list of requirements from a string.


Instruction:
Can you write a function in Python 3 where it
sets up global resource manager ( deliberately not state - saved )

Response:
def _initialize(g=globals()):
    "Set up global resource manager (deliberately not state-saved)"
    manager = ResourceManager()
    g['_manager'] = manager
    for name in dir(manager):
        if not name.startswith('_'):
            g[name] = getattr(manager, name)


Instruction:
Create a Python 3 function to
initialize the master working set and sets the entry points and the main run script.

Response:
def _initialize_master_working_set():
    """
    Prepare the master working set and make the ``require()``
    API available.

    This function has explicit effects on the global state
    of pkg_resources. It is intended to be invoked once at
    the initialization of this module.

    Invocation by other packages is unsupported and done
    at their own risk.
    """
    working_set = WorkingSet._build_master()
    _declare_state('object', working_set=working_set)

    require = working_set.require
    iter_entry_points = working_set.iter_entry_points
    add_activation_listener = working_set.subscribe
    run_script = working_set.run_script
    # backward compatibility
    run_main = run_script
    # Activate all distributions already on sys.path, and ensure that
    # all distributions added to the working set in the future (e.g. by
    # calling ``require()``) will get activated as well.
    add_activation_listener(lambda dist: dist.activate())
    working_set.entries=[]
    # match order
    list(map(working_set.add_entry, sys.path))
    globals().update(locals())


Instruction:
Write a Python 3 function for
protecting against re - patching distutils if reloaded

Response:
def _get_unpatched(cls):
    """Protect against re-patching the distutils if reloaded

    Also ensures that no other distutils extension monkeypatched the distutils
    first.
    """
    while cls.__module__.startswith('setuptools'):
        cls, = cls.__bases__
    if not cls.__module__.startswith('distutils'):
        raise AssertionError(
            "distutils has already been patched by %r" % cls
        )
    return cls


Instruction:
Here you have a function in Python 3, explain what it does
def _patch_distribution_metadata_write_pkg_info():
    environment_local = (3,) <= sys.version_info[:3] < (3, 2, 2)
    if not environment_local:
        return

    # from Python 3.4
    def write_pkg_info(self, base_dir):
        """Write the PKG-INFO file into the release tree.
        """
        with open(os.path.join(base_dir, 'PKG-INFO'), 'w',
                  encoding='UTF-8') as pkg_info:
            self.write_pkg_file(pkg_info)

    distutils.dist.DistributionMetadata.write_pkg_info = write_pkg_info

Response: Patch distutils. dist. DistributionMetadata. write_pkg_info to use the PKG - INFO file.


Instruction:
Make a summary of the following Python 3 code
def check_extras(dist, attr, value):
    try:
        for k,v in value.items():
            if ':' in k:
                k,m = k.split(':',1)
                if pkg_resources.invalid_marker(m):
                    raise DistutilsSetupError("Invalid environment marker: "+m)
            list(pkg_resources.parse_requirements(v))
    except (TypeError,ValueError,AttributeError):
        raise DistutilsSetupError(
            "'extras_require' must be a dictionary whose values are "
            "strings or lists of strings containing valid project/version "
            "requirement specifiers."
        )

Response: Verify that extras_require mapping is valid.


Instruction:
Here you have a function in Python 3, explain what it does
def check_requirements(dist, attr, value):
    try:
        list(pkg_resources.parse_requirements(value))
    except (TypeError, ValueError) as error:
        tmpl = (
            "{attr!r} must be a string or list of strings "
            "containing valid project/version requirement specifiers; {error}"
        )
        raise DistutilsSetupError(tmpl.format(attr=attr, error=error))

Response: Verify that install_requires is a valid requirements list


Instruction:
Write a Python 3 function that can
fetch an egg needed for building

Response:
def fetch_build_egg(self, req):
        """Fetch an egg needed for building"""

        try:
            cmd = self._egg_fetcher
            cmd.package_index.to_scan = []
        except AttributeError:
            from setuptools.command.easy_install import easy_install
            dist = self.__class__({'script_args':['easy_install']})
            dist.parse_config_files()
            opts = dist.get_option_dict('easy_install')
            keep = (
                'find_links', 'site_dirs', 'index_url', 'optimize',
                'site_dirs', 'allow_hosts'
            )
            for key in list(opts):
                if key not in keep:
                    del opts[key]   # don't use any other settings
            if self.dependency_links:
                links = self.dependency_links[:]
                if 'find_links' in opts:
                    links = opts['find_links'][1].split() + links
                opts['find_links'] = ('setup', links)
            install_dir = self.get_egg_cache_dir()
            cmd = easy_install(
                dist, args=["x"], install_dir=install_dir, exclude_scripts=True,
                always_copy=False, build_directory=None, editable=False,
                upgrade=False, multi_version=True, no_report=True, user=False
            )
            cmd.ensure_finalized()
            self._egg_fetcher = cmd
        return cmd.easy_install(req)


Instruction:
Implement a function in Python 3 to
handle include()' for list or tuple attrs without a special handler.

Response:
def _include_misc(self,name,value):
        """Handle 'include()' for list/tuple attrs without a special handler"""

        if not isinstance(value,sequence):
            raise DistutilsSetupError(
                "%s: setting must be a list (%r)" % (name, value)
            )
        try:
            old = getattr(self,name)
        except AttributeError:
            raise DistutilsSetupError(
                "%s: No such distribution setting" % name
            )
        if old is None:
            setattr(self,name,value)
        elif not isinstance(old,sequence):
            raise DistutilsSetupError(
                name+": this setting cannot be changed via include/exclude"
            )
        else:
            setattr(self,name,old+[item for item in value if item not in old])


Instruction:
Write a Python 3 function for
rolling n - sided dice and return each result and the total

Response:
def do_dice_roll():
	"""
	Roll n-sided dice and return each result and the total
	"""
	options = get_options()
	dice = Dice(options.sides)
	rolls = [dice.roll() for n in range(options.number)]
	for roll in rolls:
		print('rolled', roll)
	if options.number > 1:
		print('total', sum(rolls))


Instruction:
How would you explain what the following Python 3 function does
def price_converter(obj):
    if isinstance(obj, str):
        obj = PriceClass.parse(obj)
    return obj

Response: Ensures that string prices are converted into Price objects.


Instruction:
Can you create a Python 3 function that
returns a new attribute that can be used to set the price of the current object.

Response:
def price(*args, **kwargs):
    """Price field for attrs.

    See `help(attr.ib)` for full signature.

    Usage:

        >>> from pricing import fields
        ... @attr.s
        ... class Test:
        ...     price: Price = fields.price(default='USD 5.00')
        ...
        ... Test()
        Test(price=USD 5.00)
    """

    kwargs.setdefault('default', 'USD 0.00')
    kwargs.setdefault('converter', price_converter)

    if 'validator' in kwargs:
        validator = kwargs.pop('validator')
        if not isinstance(validator, (tuple, list)):
            validator = [validator]
    else:
        validator = []
    validator.append(instance_of(PriceClass))
    return attr.ib(validator=validator, *args, **kwargs)


Instruction:
Given the following Python 3 function, write the documentation
def validate(self, request):

        try:
            validate_version(request)
            validate_method(request)
            validate_params(request)
            validate_id(request)
        except (AssertionError, KeyError) as error:
            invalid_request(error)

Response: Validate the JSON - RPC request.


Instruction:
Can you generate a brief explanation for the following Python 3 code
def get_method(self, args):

        try:
            method = self.app[args['method']]
        except KeyError:
            method_not_found(args['id'])
        else:
            return method

Response: Get request method for service application.


Instruction:
Can you generate the documentation for the following Python 3 function
def module(self):
        from warnings import warn
        warn(DeprecationWarning('modules were deprecated in favor of '
                                'blueprints.  Use request.blueprint '
                                'instead.'), stacklevel=2)
        if self._is_old_module:
            return self.blueprint

Response:
The name of the current module if the request was dispatched
        to an actual module.


Instruction:
Can you generate the documentation for the following Python 3 function
def get_json(self, force=False, silent=False, cache=True):
        rv = getattr(self, '_cached_json', _missing)
        if rv is not _missing:
            return rv

        if self.mimetype != 'application/json' and not force:
            return None

        # We accept a request charset against the specification as
        # certain clients have been using this in the past.  This
        # fits our general approach of being nice in what we accept
        # and strict in what we send out.
        request_charset = self.mimetype_params.get('charset')
        try:
            data = _get_data(self, cache)
            if request_charset is not None:
                rv = json.loads(data, encoding=request_charset)
            else:
                rv = json.loads(data)
        except ValueError as e:
            if silent:
                rv = None
            else:
                rv = self.on_json_loading_failed(e)
        if cache:
            self._cached_json = rv
        return rv

Response: Parses the incoming JSON request data and returns it.


Instruction:
Can you generate a brief explanation for the following Python 3 code
def attach_enctype_error_multidict(request):
    oldcls = request.files.__class__
    class newcls(oldcls):
        def __getitem__(self, key):
            try:
                return oldcls.__getitem__(self, key)
            except KeyError as e:
                if key not in request.form:
                    raise
                raise DebugFilesKeyError(request, key)
    newcls.__name__ = oldcls.__name__
    newcls.__module__ = oldcls.__module__
    request.files.__class__ = newcls

Response: Monkeypatch the request. files object in case of multipart form data but the files object is accessed.


Instruction:
Implement a Python 3 function for
adding a install_req as a requirement to the set.

Response:
def add_requirement(self, install_req, parent_req_name=None):
        """Add install_req as a requirement to install.

        :param parent_req_name: The name of the requirement that needed this
            added. The name is used because when multiple unnamed requirements
            resolve to the same name, we could otherwise end up with dependency
            links that point outside the Requirements set. parent_req must
            already be added. Note that None implies that this is a user
            supplied requirement, vs an inferred one.
        :return: Additional requirements to scan. That is either [] if
            the requirement is not applicable, or [install_req] if the
            requirement is applicable and has just been added.
        """
        name = install_req.name
        if not install_req.match_markers():
            logger.warning("Ignoring %s: markers %r don't match your "
                           "environment", install_req.name,
                           install_req.markers)
            return []

        install_req.as_egg = self.as_egg
        install_req.use_user_site = self.use_user_site
        install_req.target_dir = self.target_dir
        install_req.pycompile = self.pycompile
        if not name:
            # url or path requirement w/o an egg fragment
            self.unnamed_requirements.append(install_req)
            return [install_req]
        else:
            if parent_req_name is None and self.has_requirement(name):
                raise InstallationError(
                    'Double requirement given: %s (already in %s, name=%r)'
                    % (install_req, self.get_requirement(name), name))
            if not self.has_requirement(name):
                # Add requirement
                self.requirements[name] = install_req
                # FIXME: what about other normalizations?  E.g., _ vs. -?
                if name.lower() != name:
                    self.requirement_aliases[name.lower()] = name
                result = [install_req]
            else:
                # Canonicalise to the already-added object
                install_req = self.get_requirement(name)
                # No need to scan, this is a duplicate requirement.
                result = []
            if parent_req_name:
                parent_req = self.get_requirement(parent_req_name)
                self._dependencies[parent_req].append(install_req)
            return result


Instruction:
Here you have a function in Python 3, explain what it does
def _walk_req_to_install(self, handler):
        # The list() here is to avoid potential mutate-while-iterating bugs.
        discovered_reqs = []
        reqs = itertools.chain(
            list(self.unnamed_requirements), list(self.requirements.values()),
            discovered_reqs)
        for req_to_install in reqs:
            more_reqs = handler(req_to_install)
            if more_reqs:
                discovered_reqs.extend(more_reqs)

Response: Walks the list of pending requirements and calls handler for all pending requirements.


Instruction:
Create a Python 3 function for
creating temp directories download and unpack files.

Response:
def prepare_files(self, finder):
        """
        Prepare process. Create temp directories, download and/or unpack files.
        """
        # make the wheelhouse
        if self.wheel_download_dir:
            ensure_dir(self.wheel_download_dir)

        self._walk_req_to_install(
            functools.partial(self._prepare_file, finder))


Instruction:
Implement a Python 3 function for
checking if the req_to_install should be skipped.

Response:
def _check_skip_installed(self, req_to_install, finder):
        """Check if req_to_install should be skipped.

        This will check if the req is installed, and whether we should upgrade
        or reinstall it, taking into account all the relevant user options.

        After calling this req_to_install will only have satisfied_by set to
        None if the req_to_install is to be upgraded/reinstalled etc. Any
        other value will be a dist recording the current thing installed that
        satisfies the requirement.

        Note that for vcs urls and the like we can't assess skipping in this
        routine - we simply identify that we need to pull the thing down,
        then later on it is pulled down and introspected to assess upgrade/
        reinstalls etc.

        :return: A text reason for why it was skipped, or None.
        """
        # Check whether to upgrade/reinstall this req or not.
        req_to_install.check_if_exists()
        if req_to_install.satisfied_by:
            skip_reason = 'satisfied (use --upgrade to upgrade)'
            if self.upgrade:
                best_installed = False
                # For link based requirements we have to pull the
                # tree down and inspect to assess the version #, so
                # its handled way down.
                if not (self.force_reinstall or req_to_install.link):
                    try:
                        finder.find_requirement(req_to_install, self.upgrade)
                    except BestVersionAlreadyInstalled:
                        skip_reason = 'up-to-date'
                        best_installed = True
                    except DistributionNotFound:
                        # No distribution found, so we squash the
                        # error - it will be raised later when we
                        # re-try later to do the install.
                        # Why don't we just raise here?
                        pass

                if not best_installed:
                    # don't uninstall conflict if user install and
                    # conflict is not user install
                    if not (self.use_user_site and not
                            dist_in_usersite(req_to_install.satisfied_by)):
                        req_to_install.conflicts_with = \
                            req_to_install.satisfied_by
                    req_to_install.satisfied_by = None
            return skip_reason
        else:
            return None


Instruction:
Here you have a function in Python 3, explain what it does
def _prepare_file(self, finder, req_to_install):
        # Tell user what we are doing for this requirement:
        # obtain (editable), skipping, processing (local url), collecting
        # (remote url or package name)
        if req_to_install.editable:
            logger.info('Obtaining %s', req_to_install)
        else:
            # satisfied_by is only evaluated by calling _check_skip_installed,
            # so it must be None here.
            assert req_to_install.satisfied_by is None
            if not self.ignore_installed:
                skip_reason = self._check_skip_installed(
                    req_to_install, finder)

            if req_to_install.satisfied_by:
                assert skip_reason is not None, (
                    '_check_skip_installed returned None but '
                    'req_to_install.satisfied_by is set to %r'
                    % (req_to_install.satisfied_by,))
                logger.info(
                    'Requirement already %s: %s', skip_reason,
                    req_to_install)
            else:
                if (req_to_install.link and
                        req_to_install.link.scheme == 'file'):
                    path = url_to_path(req_to_install.link.url)
                    logger.info('Processing %s', display_path(path))
                else:
                    logger.info('Collecting %s', req_to_install)

        with indent_log():
            # ################################ #
            # # vcs update or unpack archive # #
            # ################################ #
            if req_to_install.editable:
                req_to_install.ensure_has_source_dir(self.src_dir)
                req_to_install.update_editable(not self.is_download)
                abstract_dist = make_abstract_dist(req_to_install)
                abstract_dist.prep_for_dist()
                if self.is_download:
                    req_to_install.archive(self.download_dir)
            elif req_to_install.satisfied_by:
                abstract_dist = Installed(req_to_install)
            else:
                # @@ if filesystem packages are not marked
                # editable in a req, a non deterministic error
                # occurs when the script attempts to unpack the
                # build directory
                req_to_install.ensure_has_source_dir(self.build_dir)
                # If a checkout exists, it's unwise to keep going.  version
                # inconsistencies are logged later, but do not fail the
                # installation.
                # FIXME: this won't upgrade when there's an existing
                # package unpacked in `req_to_install.source_dir`
                if os.path.exists(
                        os.path.join(req_to_install.source_dir, 'setup.py')):
                    raise PreviousBuildDirError(
                        "pip can't proceed with requirements '%s' due to a"
                        " pre-existing build directory (%s). This is "
                        "likely due to a previous installation that failed"
                        ". pip is being responsible and not assuming it "
                        "can delete this. Please delete it and try again."
                        % (req_to_install, req_to_install.source_dir)
                    )
                req_to_install.populate_link(finder, self.upgrade)
                # We can't hit this spot and have populate_link return None.
                # req_to_install.satisfied_by is None here (because we're
                # guarded) and upgrade has no impact except when satisfied_by
                # is not None.
                # Then inside find_requirement existing_applicable -> False
                # If no new versions are found, DistributionNotFound is raised,
                # otherwise a result is guaranteed.
                assert req_to_install.link
                try:
                    download_dir = self.download_dir
                    # We always delete unpacked sdists after pip ran.
                    autodelete_unpacked = True
                    if req_to_install.link.is_wheel \
                            and self.wheel_download_dir:
                        # when doing 'pip wheel` we download wheels to a
                        # dedicated dir.
                        download_dir = self.wheel_download_dir
                    if req_to_install.link.is_wheel:
                        if download_dir:
                            # When downloading, we only unpack wheels to get
                            # metadata.
                            autodelete_unpacked = True
                        else:
                            # When installing a wheel, we use the unpacked
                            # wheel.
                            autodelete_unpacked = False
                    unpack_url(
                        req_to_install.link, req_to_install.source_dir,
                        download_dir, autodelete_unpacked,
                        session=self.session)
                except requests.HTTPError as exc:
                    logger.critical(
                        'Could not install requirement %s because '
                        'of error %s',
                        req_to_install,
                        exc,
                    )
                    raise InstallationError(
                        'Could not install requirement %s because '
                        'of HTTP error %s for URL %s' %
                        (req_to_install, exc, req_to_install.link)
                    )
                abstract_dist = make_abstract_dist(req_to_install)
                abstract_dist.prep_for_dist()
                if self.is_download:
                    # Make a .zip of the source_dir we already created.
                    if req_to_install.link.scheme in vcs.all_schemes:
                        req_to_install.archive(self.download_dir)
                # req_to_install.req is only avail after unpack for URL
                # pkgs repeat check_if_exists to uninstall-on-upgrade
                # (#14)
                if not self.ignore_installed:
                    req_to_install.check_if_exists()
                if req_to_install.satisfied_by:
                    if self.upgrade or self.ignore_installed:
                        # don't uninstall conflict if user install and
                        # conflict is not user install
                        if not (self.use_user_site and not
                                dist_in_usersite(
                                    req_to_install.satisfied_by)):
                            req_to_install.conflicts_with = \
                                req_to_install.satisfied_by
                        req_to_install.satisfied_by = None
                    else:
                        logger.info(
                            'Requirement already satisfied (use '
                            '--upgrade to upgrade): %s',
                            req_to_install,
                        )

            # ###################### #
            # # parse dependencies # #
            # ###################### #
            dist = abstract_dist.dist(finder)
            more_reqs = []

            def add_req(subreq):
                sub_install_req = InstallRequirement(
                    str(subreq),
                    req_to_install,
                    isolated=self.isolated,
                    wheel_cache=self._wheel_cache,
                )
                more_reqs.extend(self.add_requirement(
                    sub_install_req, req_to_install.name))

            # We add req_to_install before its dependencies, so that we
            # can refer to it when adding dependencies.
            if not self.has_requirement(req_to_install.name):
                # 'unnamed' requirements will get added here
                self.add_requirement(req_to_install, None)

            if not self.ignore_dependencies:
                if (req_to_install.extras):
                    logger.debug(
                        "Installing extra requirements: %r",
                        ','.join(req_to_install.extras),
                    )
                missing_requested = sorted(
                    set(req_to_install.extras) - set(dist.extras)
                )
                for missing in missing_requested:
                    logger.warning(
                        '%s does not provide the extra \'%s\'',
                        dist, missing
                    )

                available_requested = sorted(
                    set(dist.extras) & set(req_to_install.extras)
                )
                for subreq in dist.requires(available_requested):
                    add_req(subreq)

            # cleanup tmp src
            self.reqs_to_cleanup.append(req_to_install)

            if not req_to_install.editable and not req_to_install.satisfied_by:
                # XXX: --no-install leads this to report 'Successfully
                # downloaded' for only non-editable reqs, even though we took
                # action on them.
                self.successfully_downloaded.append(req_to_install)

        return more_reqs

Response: Prepare a single file for installing.


Instruction:
How would you explain what the following Python 3 function does
def cleanup_files(self):
        logger.debug('Cleaning up...')
        with indent_log():
            for req in self.reqs_to_cleanup:
                req.remove_temporary_source()

Response: Clean up files remove builds.


Instruction:
Write a Python 3 script for
creating the installation order.

Response:
def _to_install(self):
        """Create the installation order.

        The installation order is topological - requirements are installed
        before the requiring thing. We break cycles at an arbitrary point,
        and make no other guarantees.
        """
        # The current implementation, which we may change at any point
        # installs the user specified things in the order given, except when
        # dependencies must come earlier to achieve topological order.
        order = []
        ordered_reqs = set()

        def schedule(req):
            if req.satisfied_by or req in ordered_reqs:
                return
            ordered_reqs.add(req)
            for dep in self._dependencies[req]:
                schedule(dep)
            order.append(req)
        for install_req in self.requirements.values():
            schedule(install_req)
        return order