newstr.py 文件源码

def __contains__(self, key):
        errmsg = "'in <string>' requires string as left operand, not {0}"
        # Don't use isinstance() here because we only want to catch
        # newstr, not Python 2 unicode:
        if type(key) == newstr:
            newkey = key
        elif isinstance(key, unicode) or isinstance(key, bytes) and not isnewbytes(key):
            newkey = newstr(key)
        else:
            raise TypeError(errmsg.format(type(key)))
        return issubset(list(newkey), list(self))