Add script to prune non-free xml files

prune-nonfree.py

@@ -0,0 +1,52 @@
+""" Prune non-free ThML files """
+
+import re
+import os
+import xml.etree.ElementTree as ET
+from pathlib import Path
+
+
+def get_field(root, field):
+    try:
+        text = root.find(f".//{field}").text
+        text = re.sub(r"\s+", " ", text)
+    except:
+        text = None
+
+    return text
+
+
+def prune():
+    global count
+
+    for filename in list(Path(".").rglob("*.xml")):
+        filename = str(filename)
+        if "authInfo." in filename:
+            continue
+        try:
+            tree = ET.parse(filename)
+        except:
+            print("ERROR: Unable to parse:", filename)
+            continue
+
+        root = tree.getroot()
+
+        # Skip content with copyright restrictions
+        # The copyright statements aren’t consistent.
+        # The ones that contain the text "public domain" (case insensitive)
+        # or nothing at all should be safe.
+        rights = get_field(root, "DC.Rights")
+
+        if rights and "public domain" not in rights.lower():
+            print(f"Removed {filename} due to copyright: {rights}")
+
+
+if __name__ == "__main__":
+    print(
+        "This script will permanently delete any xml files with non-free DC.Rights under the current directory."
+    )
+    confirm = input("Type `delete` to continue: ")
+    if confirm != "delete":
+        print("Exiting without modification")
+        exit(1)
+    prune()