Langchain-core was throwing an error around trim_messages. Updating to 0.2.9 resolves it for me.
from langchain_core.messages.utils import trim_messages
ImportError: cannot import name 'trim_messages' from 'langchain_core.messages.utils' (/Users/jennifer/opt/anaconda3/envs/py312/lib/python3.12/site-packages/langchain_core/messages/utils.py)
Langchain-core was throwing an error around trim_messages. Updating to 0.2.9 resolves it for me.