docs: def add_handler(self, event, handler):
          """Adds a handler for a particular event.
  
          Handlers are appended to the list, so a handler added earlier
          will be called before a handler added later. If you wish to
          insert a handler at another position, you should modify the
          event_handlers property directly:
  
              my_client.event_handlers['PRIVMSG'].insert(0, my_handler)
          """
          if event not in self.event_handlers:
              _log.info("Adding event handler for new event %s.", event)
              self.event_handlers[event] = [handler]
          else:
              self.event_handlers[event].append(handler)