The default value of the argument is "default", but it is used like this: KeyValueStore.open(name=persist_state_kvs_name), which opens a named storage called "default" when running on Apify.

Possible solutions

1. accept a pre-opened KeyValueStore instance instead
2. accept a type that distinguishes names/IDs/nothing - kinda verbose in Python

Note - after #809, this change will be easier to do consistently.