code: def _authenticate(self):
          
          opts = {'domain': self._domain}
          opts.update(self._auth)
          response = self._api.domain.info(opts)
          self._validate_response(
              response=response, message='Failed to authenticate')
  
          # set to fake id to pass tests, inwx doesn't work on domain id but
          # uses domain names for identification
          self.domain_id = 1
  
          return True
docs: run any request against the API just to make sure the credentials
          are valid
  
          :return bool: success status
          :raises Exception: on error