new_contents: class Plugin:
      def __init__(self, vk_bot):
          self.vk_bot = vk_bot
          self.vk_bot.add_command('stop', self.stop)
  
      def stop(self):
          # TODO(spark): Answer pong to VK API
          print('Bot stopped')
          self.vk_bot.stop()
  
subject: Stop command