def VerifyReceipt(self, receipt_data, callback):
    def _OnFetch(response):
      response.rethrow()
      callback(VerifyResponse(receipt_data, response.body))
    request = {
      'receipt-data': base64.b64encode(receipt_data),
      'password': secrets.GetSecret('itunes_subscription_secret'),
      }
    self.http_client.fetch(self._settings['verify_url'], method='POST',
                           body=json.dumps(request), callback=_OnFetch)
Verifies a receipt.  Callback receives a VerifyResponse.
dataset/ETHPy150Open viewfinderco/viewfinder/backend/services/itunes_store.py/ITunesStoreClient.VerifyReceipt