Fix data-related public API (#368)
Summary:
X-link: https://github.com/pytorch/data/pull/368
This is PR aims to expose the right data-relate API.
There are two more changes made in this PR to convert public api to private api
`check_lambda_fn` -> `_check_lambda_fn`
`deprecation_warning` -> `_deprecation_warning`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76143
Reviewed By: albanD, NivekT
Differential Revision: D35798311
Pulled By: ejguan
fbshipit-source-id: b13fded5c88a533c706702fb2070c918c839dca4
(cherry picked from commit 0b534b829a2e90e1e533951c6d334fdeaa9358b9)
