code: def on_join(self, connection, event):
          
          target = event.source
          self.privmsg(target, 'Hello %s!' % target)
docs: Handles the join event and greets everone
  
          :param connection: the connection with the event
          :type connection: :class:`irc.client.ServerConnection`
          :param event: the event to handle
          :type event: :class:`irc.client.Event`
          :returns: None