python issue30681 is fixed with Python 3.10

pyquarantine/_runtime_patches.py

@@ -12,6 +12,7 @@
 # along with pyquarantine.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+from sys import version_info
 import encodings
 
 
@@ -150,27 +151,45 @@ def get_obs_local_part(value):
 setattr(email._header_value_parser, "get_obs_local_part", get_obs_local_part)
 
 
-# https://bugs.python.org/issue30681
+#######################################
+#  add charset alias for windows-874  #
+#######################################
 #
-# fix: https://github.com/python/cpython/pull/22090
+# https://bugs.python.org/issue17254
+#
+# fix: https://github.com/python/cpython/pull/10237
 
-import email.errors
-from email.errors import HeaderDefect
+aliases = encodings.aliases.aliases
+
+for alias in ["windows-874", "windows_874"]:
+    if alias not in aliases:
+        aliases[alias] = "cp874"
+
+setattr(encodings.aliases, "aliases", aliases)
 
 
-class InvalidDateDefect(HeaderDefect):
+if version_info.major == 3 and version_info.minor < 10:
+    # https://bugs.python.org/issue30681
+    #
+    # fix: https://github.com/python/cpython/pull/22090
+
+    import email.errors
+    from email.errors import HeaderDefect
+
+
+    class InvalidDateDefect(HeaderDefect):
         """Header has unparseable or invalid date"""
 
 
-setattr(email.errors, "InvalidDateDefect", InvalidDateDefect)
+    setattr(email.errors, "InvalidDateDefect", InvalidDateDefect)
 
 
-import email.utils
-from email.utils import _parsedate_tz
-import datetime
+    import email.utils
+    from email.utils import _parsedate_tz
+    import datetime
 
 
-def parsedate_to_datetime(data):
+    def parsedate_to_datetime(data):
         parsed_date_tz = _parsedate_tz(data)
         if parsed_date_tz is None:
             raise ValueError('Invalid date value or format "%s"' % str(data))
@@ -181,14 +200,14 @@ def parsedate_to_datetime(data):
                 tzinfo=datetime.timezone(datetime.timedelta(seconds=tz)))
 
 
-setattr(email.utils, "parsedate_to_datetime", parsedate_to_datetime)
+    setattr(email.utils, "parsedate_to_datetime", parsedate_to_datetime)
 
 
-import email.headerregistry
-from email import utils, _header_value_parser as parser
+    import email.headerregistry
+    from email import utils, _header_value_parser as parser
 
-@classmethod
-def parse(cls, value, kwds):
+    @classmethod
+    def parse(cls, value, kwds):
         if not value:
             kwds['defects'].append(errors.HeaderMissingRequiredValue())
             kwds['datetime'] = None
@@ -209,21 +228,4 @@ def parse(cls, value, kwds):
         kwds['parse_tree'] = cls.value_parser(kwds['decoded'])
 
 
-setattr(email.headerregistry.DateHeader, "parse", parse)
-
-
-#######################################
-#  add charset alias for windows-874  #
-#######################################
-#
-# https://bugs.python.org/issue17254
-#
-# fix: https://github.com/python/cpython/pull/10237
-
-aliases = encodings.aliases.aliases
-
-for alias in ["windows-874", "windows_874"]:
-    if alias not in aliases:
-        aliases[alias] = "cp874"
-
-setattr(encodings.aliases, "aliases", aliases)
+    setattr(email.headerregistry.DateHeader, "parse", parse)