code: def channels(self):
          
          resp = self._rtm_client.get('v1/current_team.channels')
          if resp.is_fail():
              raise RTMServiceError(
                  'Failed to get channels of current team',
                  resp
              )
          return resp.data['result']
docs: Gets channels of current team
  
          Returns:
              list of Channel
  
          Throws:
              RTMServiceError when request failed