code: def start(self):
          
          resp = self.post('start')
  
          if resp.is_fail():
              return None
          if 'result' not in resp.data:
              return None
  
          result = resp.data['result']
          return {
              'user': result['user'],
              'ws_host': result['ws_host'],
          }
docs: Gets the rtm ws_host and user information
  
          Returns:
              None if request failed,
              else a dict containing "user"(User) and "ws_host"