substrate websocket getting blocked at subscription_handler

[Jessie-1]

unable to subscribe more due to blocking.

[arjanz]

The library is intended for a sync environment, but if you aim to subscribe to multiple storage keys at once you can have a look at the subscribe_storage() function, see docs:

https://polkascan.github.io/py-substrate-interface/usage/subscriptions/#subscribe-to-multiple-storage-keys

Otherwise you can resort to work with threads, be sure to use a separate instance of SubstrateInterface per thread because otherwise it wouldn't be threadsafe. See examples mentioned in:

#206 (comment)

#82 (comment)