TypeError：元类“不带参数”

Question

为什么以下代码会出错：

class StateMeta:
    def __call__(*args, **kwargs):
        pass
    # end __call__
# end StateMeta

class State(metaclass=StateMeta):
    pass

错误：

Traceback (most recent call last):
  File "D:/FILE_MGMT_PYTHON/tempHSHDFHS).py", line 7, in <module>
    class State(metaclass=StateMeta):
TypeError: StateMeta() takes no arguments

Answer 1

您忘了让元类继承自type，写StateMeta(type)而不是StateMeta。