* Log with prefix

* Fix test of loggerhook

* minor refine

* minor refine

* Fix unit test

* clean the code

* deepcopy in method

* replace regex

* Fix as comment

* Enhance readable

* rename reserve_prefix to remove_prefix

* Fix as comment

* Refine unit test

* Adjust sequence

* clean the code

* clean the code

* revert renaming reserve prefix

* Count the dataloader length in _get_dataloader_size