ai-agents-pydantic-migration-c-using-runnablewithfallbacks-or-with-fallbacks-on-a-26060d62

THEN Ensure you are not mixing Pydantic v1 and v2 code. Either pin to Pydantic v1 and upgrade after LangChain's internal migration completes (after August 25, 2023), or perform a full migration to Pydantic v2 consistently across your project. If using partial migration, use only the correct Pydantic version when extending or passing objects to LangChain.

# Avoid mixing pydantic v1 and v2
# Option 1: pin pydantic v1
# pip install pydantic==1.10.12

# Option 2: after LangChain migration, use v2
# pip install pydantic>=2.0
# Ensure all custom code uses v2 BaseModel