Serialization mapping.
This file contains a mapping between the lc_namespace path for a given
subclass that implements from Serializable to the namespace
where that class is actually located.
This mapping helps maintain the ability to serialize and deserialize well-known LangChain objects even if they are moved around in the codebase across different LangChain versions.
For example, the code for the AIMessage class is located in
langchain_core.messages.ai.AIMessage. This message is associated with the
lc_namespace of ["langchain", "schema", "messages", "AIMessage"],
because this code was originally in langchain.schema.messages.AIMessage.
The mapping allows us to deserialize an AIMessage created with an older
version of LangChain where the code was in a different location.
