diff options
Diffstat (limited to 'Lib/abc.py')
| -rw-r--r-- | Lib/abc.py | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/Lib/abc.py b/Lib/abc.py index 5da2590e4f..5e90bf5f1a 100644 --- a/Lib/abc.py +++ b/Lib/abc.py @@ -116,18 +116,18 @@ class ABCMeta(type): def __instancecheck__(cls, instance): """Override for isinstance(instance, cls).""" - # Inline the cache checking for new-style classes. - subclass = instance.__class__ + # Inline the cache checking when it's simple. + subclass = getattr(instance, '__class__', None) if subclass in cls._abc_cache: return True subtype = type(instance) - if subtype is subclass: + if subtype is subclass or subclass is None: if (cls._abc_negative_cache_version == ABCMeta._abc_invalidation_counter and - subclass in cls._abc_negative_cache): + subtype in cls._abc_negative_cache): return False # Fall back to the subclass check. - return cls.__subclasscheck__(subclass) + return cls.__subclasscheck__(subtype) return (cls.__subclasscheck__(subclass) or cls.__subclasscheck__(subtype)) |