decorators.py 文件源码

def __call__(self, fn, *args, **kwargs):
        try:
            fn._decorators.append(self)
        except AttributeError:
            fn._decorators = [self]

        # Verify function signature
        argspec = inspect.getfullargspec(fn)
        n_args = len(argspec.args) - 1 if 'self' in argspec.args else len(argspec.args)
        assert n_args >= 1, 'Functions decorated with @Subscribe must have a parameter for the message.'

        n_required_args = n_args - (len(argspec.defaults) if argspec.defaults else 0)
        assert n_required_args <= 1, 'Functions decorated with @Subscribe can only have one required parameter.'

        # Add typing information if not already defined
        first_arg = argspec.args[1] if 'self' in argspec.args else argspec.args[0]
        if first_arg not in argspec.annotations.keys():
            fn.__annotations__[first_arg] = self.subs[-1]

        return fn