class MeshMeta(type):
def __instancecheck__(cls, inst):
"""Implement isinstance(inst, cls)."""
return any(cls.__subclasscheck__(c)
for c in {type(inst), inst.__class__})
def __subclasscheck__(cls, sub):
"""Implement issubclass(sub, cls)."""
return type.__subclasscheck__(cls, sub) or (cls.__name__ == sub.__name__ and cls.__module__ == sub.__module__)
...
class Mesh:
__metaclass__ = MeshMeta
...
