Clarify and expand auto_get_columns() docstring
Clarify and expand auto_get_columns() docstring

bendmorris/retriever,embaldridge/retriever,goelakash/retriever,embaldridge/retriever,bendmorris/retriever,davharris/retriever,davharris/retriever,henrykironde/deletedret,bendmorris/retriever,henrykironde/deletedret,embaldridge/retriever,goelakash/retriever,davharris/retriever