def _keytuple(obj):  # PYCHOK expected
        '''Return class and instance keys for a class.
        '''
        if type(obj) is _Type_type:  # isclass(obj):
            return _claskey(obj, _new_style), obj
        return None, None  # not a class
Return class and instance keys for a class.
        
recipes/Python/546530_Size_of_Python_objects_revised/recipe-546530.py