def leave(self, channel, reason=None):
        """
        Leave a channel.

        @type channel: C{str}
        @param channel: The name of the channel to leave. If it has no prefix,
            C{'#'} will be prepended to it.
        @type reason: C{str}
        @param reason: If given, the reason for leaving.
        """
        if channel[0] not in CHANNEL_PREFIXES:
            channel = '#' + channel
        if reason:
            self.sendLine((channel, reason) % "PART %s :%s")
        else:
            self.sendLine("PART %s" % (channel,))
dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/words/protocols/irc.py/IRCClient.leave/swapped operands of `%`