Add compatibility code for Python 2.7

- Typo in codepoints.py for compat chr()
  - Add a fake lru_cache decorator for Python 2.7

xmlschema/codepoints.py

@@ -494,7 +494,7 @@ def get_unicodedata_categories():
     minor_category = 'Cc'
     start_cp, next_cp = 0, 1
     for cp in range(maxunicode + 1):
-        if category(chr(cp)) != minor_category:
+        if category(unicode_chr(cp)) != minor_category:
             if cp > next_cp:
                 categories[minor_category].append((start_cp, cp))
                 categories[minor_category[0]].append(categories[minor_category][-1])
@@ -502,7 +502,7 @@ def get_unicodedata_categories():
                 categories[minor_category].append(start_cp)
                 categories[minor_category[0]].append(start_cp)
 
-            minor_category = category(chr(cp))
+            minor_category = category(unicode_chr(cp))
             start_cp, next_cp = cp, cp + 1
     else:
         if next_cp == maxunicode + 1:

xmlschema/compat.py

@@ -21,6 +21,7 @@ try:
     from urllib.error import URLError
     from io import StringIO, BytesIO
     from collections.abc import Iterable, MutableSet, Sequence, MutableSequence, Mapping, MutableMapping
+    from functools import lru_cache
 except ImportError:
     # Python 2.7 imports
     from urllib import pathname2url
@@ -29,6 +30,18 @@ except ImportError:
     from StringIO import StringIO  # the io.StringIO accepts only unicode type
     from io import BytesIO
     from collections import Iterable, MutableSet, Sequence, MutableSequence, Mapping, MutableMapping
+    from functools import wraps
+
+    def lru_cache(maxsize=128, typed=False):
+        """
+        A fake lru_cache decorator function for Python 2.7 compatibility until support ends.
+        """
+        def lru_cache_decorator(f):
+            @wraps(f)
+            def wrapper(*args, **kwargs):
+                return f(*args, **kwargs)
+            return wrapper
+        return lru_cache_decorator
 
 
 PY3 = sys.version_info[0] == 3