session.submit_payment throws error: null task_token

[origamih]

Hi all,
I'm using this SDK with the demo credentials.
I was trying to test the payment, with this snippet:

const submitPayment = (accessToken, payment, tanSchemeId, state, redirectUri) => {
  return new Promise((resolve, reject) => {
    const session = new figo.Session(accessToken);
    session.submit_payment(payment, tanSchemeId, state, redirectUri, (error, returnUrl) => {
      if (error) {
        console.log(error);
        return reject(error);
      }
      return resolve(returnUrl);
    });
  });
};

const mockPayment = {
  type: 'SEPA transfer',
  name: 'Koodaa',
  amount: 5.5,
  purpose: 'test',
  account_id: 'A1.1',
  account_number: '4711951502',
  bank_code: '90090042',
  iban: ''
};
test('should be able to submit payment', async () => {
    // addPayment will call session.add_payment and return a payment object
    const payment = await addPayment(accessToken, mockPayment);
    // submitPayment will call session.submit_payment (check above code)
    const returnUrl = await submitPayment(accessToken, payment, '111111', 'state');
    ...
  });

And I got this:

/node_modules/figo/lib/figo.js:1090
        callback(null, "https://" + Config.api_endpoint + "/task/start?id=" + result.task_token);
                                                                                                                         ^
TypeError: Cannot read property 'task_token' of null

Which I believe to be an error inside /lib/figo.js since it's doesn't invoke the callback with error but result, and this result object is null.

P.S: Please improve the documentation for this Nodejs SDK, I need to did into the source code to find out how it work. Thank you!