class A:
pass
class B(A):
pass
assert issubclass(A, A)
assert issubclass(B, A)
assert not issubclass(A, B)
class MCNotSubClass(type):
def __subclasscheck__(self, subclass):
return False
class NotSubClass(metaclass=MCNotSubClass):
pass
class InheritedNotSubClass(NotSubClass):
pass
assert not issubclass(A, NotSubClass)
assert not issubclass(NotSubClass, NotSubClass)
assert not issubclass(InheritedNotSubClass, NotSubClass)
assert not issubclass(NotSubClass, InheritedNotSubClass)
class MCAlwaysSubClass(type):
def __subclasscheck__(self, subclass):
return True
class AlwaysSubClass(metaclass=MCAlwaysSubClass):
pass
class InheritedAlwaysSubClass(AlwaysSubClass):
pass
assert issubclass(A, AlwaysSubClass)
assert issubclass(AlwaysSubClass, AlwaysSubClass)
assert issubclass(InheritedAlwaysSubClass, AlwaysSubClass)
assert issubclass(AlwaysSubClass, InheritedAlwaysSubClass)
class MCAVirtualSubClass(type):
def __subclasscheck__(self, subclass):
return subclass is A
class AVirtualSubClass(metaclass=MCAVirtualSubClass):
pass
assert issubclass(A, AVirtualSubClass)
assert not isinstance(B, AVirtualSubClass)