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| """The singleton metaclass for ensuring only one instance of a class.""" |
| import abc |
| from typing import Any |
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| class Singleton(abc.ABCMeta, type): |
| """Singleton metaclass for ensuring only one instance of a class""" |
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| _instances = {} |
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| def __call__(cls, *args: Any, **kwargs: Any) -> Any: |
| """Call method for the singleton metaclass""" |
| if cls not in cls._instances: |
| cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs) |
| return cls._instances[cls] |
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| class AbstractSingleton(abc.ABC, metaclass=Singleton): |
| """Abstract singleton class for ensuring only one instance of a class""" |
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| pass |
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