isinstance(object, cls)
Test whether an object is an instance of a type.
This works even if the object is security proxied:
>>> class C1(object): ... pass>>> c = C1() >>> isinstance(c, C1) True>>> from zope.security.checker import ProxyFactory >>> isinstance(ProxyFactory(c), C1) True>>> class C2(C1): ... pass>>> c = C2() >>> isinstance(c, C1) True>>> from zope.security.checker import ProxyFactory >>> isinstance(ProxyFactory(c), C1) True