langchain0.2.1版本中pydantic_v1已被移除掉
解决办法
pip install langchain_classic
from langchain_classic.memory import ConversationBufferWindowMemory
ModuleNotFoundError: No module named langchain_core.pydantic_v1
学而不思则罔，思而不学则殆！
langchain0.2.1版本中pydantic_v1已被移除掉
pip install langchain_classic
from langchain_classic.memory import ConversationBufferWindowMemory