text: from abc import ABCMeta, abstractmethod
  from .event_base import EventBase
  
  
  class TunnelEvents:
      '''Tunnel Events defination
      '''
      Request = 'REQUEST'
  
  
  class TunnelBase(EventBase):
      ''' Tunnel Base
      '''
      __metaclass__ = ABCMeta
  
      @abstractmethod
      def setup(self):
          ''' Prepare the tunnel
          '''
  
      @abstractmethod
      def notify(self, notify_type, *other):
          ''' Notify to clients
          '''
  