diff options
Diffstat (limited to 'Lib/typing.py')
| -rw-r--r-- | Lib/typing.py | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/Lib/typing.py b/Lib/typing.py index 05b65b7..557fa58 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -993,7 +993,10 @@ class GenericMeta(TypingMeta, abc.ABCMeta): # This allows unparameterized generic collections to be used # with issubclass() and isinstance() in the same way as their # collections.abc counterparts (e.g., isinstance([], Iterable)). - self.__subclasshook__ = _make_subclasshook(self) + if ('__subclasshook__' not in namespace and extra # allow overriding + or hasattr(self.__subclasshook__, '__name__') and + self.__subclasshook__.__name__ == '__extrahook__'): + self.__subclasshook__ = _make_subclasshook(self) if isinstance(extra, abc.ABCMeta): self._abc_registry = extra._abc_registry return self |