new_contents: from linebot.models import Event, MessageEvent
  from .reply_generator import ReplyGenerator
  from .event_processor import event_processor, message_event_processor
  
  class Router():
      def __init__(self, reply_generator, message_event_processors):
          self.__reply_generator = reply_generator
          self.__message_event_processors = message_event_processors
  
      def relay(self, event):
          if isinstance(event, MessageEvent):
              self.relay_message_event(event)
          else:
              print('event: ', event, 'is not MessageEvent')
  
      def relay_message_event(self, event):
          for mep in self.__message_event_processors:
              if mep.can_process(event):
                  mep.process(event, self.__reply_generator)
                  break
  
  
subject: Add Router class