cpython/Lib/test/test_unittest/testmock/support.py

target = {'foo': 'FOO'}


def is_instance(obj, klass):
    """Version of is_instance that doesn't access __class__"""
    return issubclass(type(obj), klass)


class SomeClass(object):
    class_attribute = None

    def wibble(self): pass


class X(object):
    pass