def test_get(self, get):
     ret = SingleListPartRegistry.get()
     self.assertEqual(ret, 'return')
     get.assert_called_once_with('')
 def test_add_part(self, add_part):
     id_obj = object()
     SingleListPartRegistry.add_part(id_obj)
     add_part.assert_called_once_with('', id_obj)