fields.py 文件源码

def contribute_to_class(self, cls, name, virtual_only=False):
        super().contribute_to_class(cls, name, virtual_only=False)
        setattr(cls, '_fsm_state_field', name)
        pre_save.connect(
            self._fsm_check_transitions, sender=cls,
            dispatch_uid='_fsm_check_transitions')