def join(self, channel):
        """Add this user to the channel's user list and add the channel to this
        user's list of joined channels.
        """
        
        if channel not in self.channels:
            channel.users.add(self.nick)
            self.channels.append(channel)
def join ( self , channel ) : if channel not in self . channels : channel . users . add ( self . nick ) self . channels . append ( channel )
Add this user to the channel's user list and add the channel to this
        user's list of joined channels.