attr.py 文件源码

def __init__(self, parent_dispatch_cls, fn):
        self.__name__ = fn.__name__
        argspec = util.inspect_getargspec(fn)
        self.arg_names = argspec.args[1:]
        self.has_kw = bool(argspec.keywords)
        self.legacy_signatures = list(reversed(
            sorted(
                getattr(fn, '_legacy_signatures', []),
                key=lambda s: s[0]
            )
        ))
        self.__doc__ = fn.__doc__ = legacy._augment_fn_docs(
            self, parent_dispatch_cls, fn)

        self._clslevel = weakref.WeakKeyDictionary()
        self._empty_listeners = weakref.WeakKeyDictionary()