@roo_validator error when importing langchain.text_splitter Python

I have been working through a LangChain tutorial and have hit this problem when trying to import langchain into python in vscode on macos 13.4.1.

`from dotenv import load_dotenv
import os
import streamlit as st
from PyPDF2 import PdfReader
from langchain.text_splitter import CharacterTextSplitter


def main():
    load_dotenv()
    # print(os.getenv("OPENAI_API_KEY"))
    st.set_page_config(page_title="Select the Data PDF")
    st.header("Load your PDF below: ⚡︎")

    pdf = st.file_uploader("Upload your PDF", type="pdf")

    if pdf is not None:
        pdf_reader = PdfReader(pdf)

        # the PdfReader reads in chunks of one page each
        text = ""
        for page in pdf_reader.pages:
            text += page.extract_text()
            st.write(text)
   
    # split text into chunks (inside outer if not None)
    # the CharacterTextSplitter class has properties that  need to be set...
    # so pass in property parameters to the class inititializer
    text_splitter = CharacterTextSplitter(
        separator="\n",
        chunk_size=1000,
        chunk_overlap=200,
        length_function=len #python's basic length function
        )
    chunks = text_splitter.split_text(text)
    st.write(chunks)



if __name__ == '__main__' :
    main()`

I see a suggested fix, but I do not understand how to implement it.

I get the following error on the Stringlit web page and the VSCode terminal:
PydanticUserError: If you use @root_validator with pre=False (the default) you MUST specify skip_on_failure=True. Note that @root_validator is deprecated and should be replaced with @model_validator. For further information visit https://errors.pydantic.dev/2.0/u/root-validator-pre-skip
Traceback:
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/streamlit/runtime/scriptrunner/script_runner.py", line 552, in _run_script
exec(code, module.dict)
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/app.py", line 6, in <module>
from langchain.embeddings import ImportError
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/init.py", line 8, in <module>
from langchain.agents import MRKLChain, ReActChain, SelfAskWithSearchChain
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/agents/init.py", line 2, in <module>
from langchain.agents.agent import Agent
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/agents/agent.py", line 11, in <module>
from langchain.chains.llm import LLMChain
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/chains/init.py", line 2, in <module>
from langchain.chains.conversation.base import ConversationChain
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/chains/conversation/base.py", line 7, in <module>
from langchain.chains.conversation.memory import ConversationBufferMemory
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/chains/conversation/memory.py", line 7, in <module>
from langchain.chains.conversation.prompt import SUMMARY_PROMPT
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/chains/conversation/prompt.py", line 2, in <module>
from langchain.prompts.prompt import PromptTemplate
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/prompts/init.py", line 2, in <module>
from langchain.prompts.base import BasePromptTemplate
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/prompts/base.py", line 35, in <module>
class BasePromptTemplate(BaseModel, ABC):
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/langchain/prompts/base.py", line 41, in BasePromptTemplate
@root_validator()
File "/Users/jamesallison/Desktop/Python Apps Temp/LangchainPDF/.venv/lib/python3.8/site-packages/pydantic/deprecated/class_validators.py", line 228, in root_validator
raise PydanticUserError(

I had this issue when I updated my pydantic version to 2.0.3, tried many thing but nothing worked.

Later, I observed many that imports from OpenAI and langchain requires pydantic to be less than version 2.

I lowered pydantic to 1.10.2 (and python 3.10.6) and everything worked just fine.

pip install pydantic==1.10.2

What is your Python and Langchain version? I was using 0.0.20 and I got the same issue. Upgrading to Python3.9 and langchain 0.0.224 fixed this issue for me.

Worked with below versions:

Python 3.7.12
langchain  0.0.27
pydantic 1.10.9