new_contents: class ApiSubscribeRequest(object):
      """Api request class."""
  
      def __init__(self, transport):
          self._transport = transport
          self._action = None
          self._request = {}
          self._params = {'method': 'GET',
                          'url': None,
                          'request_delete_keys': [],
                          'params': {},
                          'headers': {},
                          'response_key': None}
  
      def action(self, action):
          self._action = action
  
      def set(self, key, value):
          if not value:
              return
          self._request[key] = value
  
      def method(self, method):
          self._params['method'] = method
  
      def url(self, url, **args):
          for key in args:
              value = args[key]
              url = url.replace('{%s}' % key, str(value))
          self._params['url'] = url
  
      def param(self, key, value):
          if not value:
              return
          self._params['params'][key] = value
  
      def header(self, name, value):
          self._params['headers'][name] = value
  
      def response_key(self, response_key):
          self._params['response_key'] = response_key
  
      def extract(self):
          return self._action, self._request, self._params
  
subject: Add api_subscribe_request.py