fix: A bug fix Update models.py

[haozheng95]

fix error

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context.
I ran into this problem when I wanted to run the project. This was an issue（https://github.com/pydantic/pydantic/issues/3320） with pydantic, I fixed it by changing the properties of the models and my project was successfully running locally

My Python 3.11.9

Checklist before requesting a review

Please delete options that are not relevant.

• My code follows the style guidelines of this project
• I have performed a self-review of my code

Screenshots (if appropriate):

File "/Users/baizhe/PycharmProjects/myquivr/.venv1/lib/python3.11/site-packages/pydantic/v1/validators.py", line 765, in find_validators
    raise RuntimeError(f'no validator found for {type_}, see `arbitrary_types_allowed` in Config')
RuntimeError: no validator found for <class 'langchain_core.documents.base.Document'>, see `arbitrary_types_allowed` in Config

[StanGirard]

@jacopo-chevallard can you check this one please ?