To switch to deployed ledger-bitcoin

https://github.com/LedgerHQ/app-exchange/tree/develop/test/python/apps/bitcoin_client seems to be a diverged copy of https://github.com/LedgerHQ/app-bitcoin-new/tree/develop/bitcoin_client which is deployed officially to pypi: https://pypi.org/project/ledger-bitcoin/.
To see if in the context of  app-exchange it is feasible to use this official version, with some changes probably). 