Transaction Not In Progress, Cannot Be Used In Api Requests. Firestore Error

I am learning transactions on firestore and I making some modifications to the sample functions of documentation but I'm not sure why I get 'Transaction not in progress...' when I

Solution 1:

The function, or better to say the decorator @firestore.transactional was an essential part of the logic. The error message means you didn't start the transaction, you've just instantiated a trnsaction object.

You could begin the transaction manually using transaction._begin, but I'd strangly suggest against it. Just use the decorater which provides simple way to manage transactions, including for example error handling.