Cannot find implementation or library stub for module named "langchain.pydantic_v1" Mypy import-not-found

[austinmw]

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Example Code

from langchain.pydantic_v1 import BaseModel, Field, conlist

Description

I'm trying to use mypy for my project, but I get this error:

Cannot find implementation or library stub for module named "langchain.pydantic_v1"Mypyimport-not-found

Does LangChain support mypy?

System Info

Latest langchain version

[dosubot[bot]]

LangChain does not fully support mypy for both pydantic v1 and v2 at once due to current limitations in pydantic itself. To resolve the "Cannot find implementation or library stub for module named 'langchain.pydantic_v1'" error, you can create a stub file for langchain.pydantic_v1. Create a file named pydantic_v1.pyi in the langchain directory with the following content:

# langchain/pydantic_v1.pyi

from pydantic import *  # type: ignore

This should help mypy recognize the langchain.pydantic_v1 module ^[1][2][3][4].

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