def join(self, channel, key=None):
        """
        Join a channel.

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