[ERROR] Runtime.ImportModuleError: Unable to import module 'index_creation_app': cannot import name 'BaseCache' from 'langchain'

`Read-source-and-build-index-fn` Lambda Function is failing with:

```
[ERROR] Runtime.ImportModuleError: Unable to import module 'index_creation_app': cannot import name 'BaseCache' from 'langchain' (/var/task/langchain/__init__.py)Traceback (most recent call last): | [ERROR] Runtime.ImportModuleError: Unable to import module 'index_creation_app': cannot import name 'BaseCache' from 'langchain' (/var/task/langchain/__init__.py) Traceback (most recent call last):
-- | --

```

Start by locating the Read-source-and-build-index-fn Lambda and its index_creation_app module, then inspect the packaged langchain dependency and the import that references BaseCache. Reproduce the deployment or import failure and verify that the Lambda can load index_creation_app successfully without the ImportModuleError.

Written by the indexing model from the issue text.