Sample test file requires access to a specific account

If a run the test file it fails with:

```
Getting USD Card...
Traceback (most recent call last):
  File "samples/test.py", line 32, in <module>
    print(usd_card['label'])
KeyError: 'label'
```

because it tries to always fetch the card with id `20c0ccf3-e316-40c1-8a2a-982dd92a96ca`.
