Langchain.schema is not available while using in python code

OSS Product Help LangChain
1

“from langchain.schema import SystemMessage”

“from langchain.chains import LLMChain”

How to get schema and chains from langchain? Because, I install langchain in python scripts. And it is not working. I cross verified in the Lib>sitepackages>langchain. But not found the any file schema or chains.. Please help me to work this?

2

Those imports are from LangChain classic — to use them install:
pip install langchain-classic

However if you want to use the new version, install langchain-core and update your imports:

from langchain_core.messages import SystemMessage

3

I think this should work:

  1. SystemMessage → from langchain.messages import SystemMessage (re-export of langchain_core.messages).
  2. LLMChain quick fix → pip install langchain-classic then from langchain_classic.chains import LLMChain.
  3. LLMChain proper migration → use LCEL (prompt | model | StrOutputParser()) or create_agent from langchain.agents.
4

Thank you.

5

Thanks a lot