Fix PydanticSerializationError

✅ Solution

PydanticSerializationError in LlamaIndex often arises when attempting to serialize objects with types unsupported by Pydantic's default serializers, like those from external libraries (e.g., Google's generative AI tools). To fix it, either convert the problematic object to a serializable format like a dictionary or string before storing it, or define a custom Pydantic serializer/deserializer using `pydantic.field_serializer` and `pydantic.field_validator` to handle the specific unsupported type. Apply these to the relevant Pydantic model fields within your LlamaIndex data structures (e.g., within the chat store's message schema).