langchain

0b4fa89b - langchain[patch]: add `aprep_output` method to `langchain/chains/base.py` (#20748)

langchain[patch]: add `aprep_output` method to `langchain/chains/base.py` (#20748) ## Description Add `aprep_output` method to `langchain/chains/base.py`. Some downstream `ChatMessageHistory` objects that use async connections require an async way to append to the context. It turned out that `ainvoke()` was calling `prep_output` which is synchronous. --------- Co-authored-by: Bagatur <22008038+baskaryan@users.noreply.github.com>