types.py 文件源码

def options(self, options):
        if options is None:
            self._options = None
        elif isinstance(options, abc.Iterable):
            self._options = tuple(options)
            # Purge new invalid items
            for name in ('_default', '_value'):
                lst = getattr(self, name)
                invalid_items = set(lst).difference(self.options)
                for item in invalid_items:
                    while item in lst:
                        lst.remove(item)
        else:
            raise TypeError('options must be sequence or None, not %s: %r' % (type(options).__name__, options))