code: def _request(http, project, method, data, base_url):
      
      headers = {
          "Content-Type": "application/x-protobuf",
          "User-Agent": connection_module.DEFAULT_USER_AGENT,
          connection_module.CLIENT_INFO_HEADER: _CLIENT_INFO,
      }
      api_url = build_api_url(project, method, base_url)
  
      response = http.request(url=api_url, method="POST", headers=headers, data=data)
  
      if response.status_code != 200:
          error_status = status_pb2.Status.FromString(response.content)
          raise exceptions.from_http_status(
              response.status_code, error_status.message, errors=[error_status]
          )
  
      return response.content
docs: Make a request over the Http transport to the Cloud Datastore API.
  
      :type http: :class:`requests.Session`
      :param http: HTTP object to make requests.
  
      :type project: str
      :param project: The project to make the request for.
  
      :type method: str
      :param method: The API call method name (ie, ``runQuery``,
                     ``lookup``, etc)
  
      :type data: str
      :param data: The data to send with the API call.
                   Typically this is a serialized Protobuf string.
  
      :type base_url: str
      :param base_url: The base URL where the API lives.
  
      :rtype: str
      :returns: The string response content from the API call.
      :raises: :class:`google.cloud.exceptions.GoogleCloudError` if the
               response code is not 200 OK.