code: def _make_token_request(session, token_request_data):
      
      try:
          r = session.post(OAUTH2_TOKEN_REQUEST_URL, data=token_request_data)
          r.raise_for_status()
      except requests.RequestException as e:
          raise GoogleAuthError('Token request failed: {}'.format(e))
      else:
          res = r.json()
          # If an error occurred, a key 'error' will contain an error code.
          if 'error' in res:
              raise GoogleAuthError(
                  'Token request error: {!r}'.format(res['error'])
              )
          return res
docs: Make OAuth token request.
  
      Raises GoogleAuthError if authentication fails.
  
      Returns dict response.