* fix dataset wrapper bug and add unit tests
* fix dataset wrapper bug and add unit tests
* update unit tests
* fix lint
* align interface to mmdet
* update unit tests
* add imagnet21k
* Update unit test
* update imaenet21k
* use slots
* use slots
* rename Data_item to ImageInfo
* add unit tests
* Update unit tests
* rm some print
* update unit tests
* fix lint
* remove default value of pipeline