code: def attach_mock(self, mock, attribute):
          
          mock._mock_parent = None
          mock._mock_new_parent = None
          mock._mock_name = ''
          mock._mock_new_name = None
  
          setattr(self, attribute, mock)
docs: Attach a mock as an attribute of this one, replacing its name and
          parent. Calls to the attached mock will be recorded in the
          `method_calls` and `mock_calls` attributes of this one.