old_contents: class Event:
      def __init__(self, bot, data):
          self.bot = bot
          self.data = data
      def post_message(self, text, channel=None):
          if channel is None:
              channel = self.data['channel']
          self.bot.post_message(text, channel)
      def add_reaction(self, emoji, channel=None, timestamp=None):
          if channel is None:
              channel = self.data['channel']
          if timestamp is None:
              timestamp = self.data['ts']
          self.bot.add_reaction(emoji, channel, timestamp)
      def remove_reaction(self, emoji, channel=None, timestamp=None):
          if channel is None:
              channel = self.data['channel']
          if timestamp is None:
              timestamp = self.data['ts']
          self.bot.remove_reaction(emoji, channel, timestamp)
  
new_contents: class Event:
      def __init__(self, bot, data):
          self.bot = bot
          self.data = data
      def post_message(self, text, channel=None):
          if channel is None:
              channel = self.data['channel']
          return self.bot.post_message(text, channel)
      def add_reaction(self, emoji, channel=None, timestamp=None):
          if channel is None:
              channel = self.data['channel']
          if timestamp is None:
              timestamp = self.data['ts']
          return self.bot.add_reaction(emoji, channel, timestamp)
      def remove_reaction(self, emoji, channel=None, timestamp=None):
          if channel is None:
              channel = self.data['channel']
          if timestamp is None:
              timestamp = self.data['ts']
          return self.bot.remove_reaction(emoji, channel, timestamp)
  
subject: Add missing return of Event methods