* add initializers and BaseModule for unified parameter initialization
* fix circle import
* bug fix
* add is_init flag in BaseModule
* fix docstring
* sort import and fix doc format
* fix bug
* fix docformat and double quote string
* fix import sort
* import sort
* sort import
* revise according to comments
* fix doc format
* revise according to comments
* revise import and fix typo
* polish code
* revise minors
* revice minors
* revise apply function
* revise bias initialization with probability
* add type test for bias_prob
* revise minors
* Refactor _load_checkpoint fn
* Update _load_checkpoint fn
* Update docs str and add unit test
* Fix unit test
* Fix lint
* Add comment and Optimize function
* Fix docs str
* Update load_ckpt and fix doc str
* Update doc str and add sort unit test
* Update and fix unit test
* Fix unit test
* Update and add unit test
* Fix openmmlab prefix error
* fix: remove all module wrapper when saving checkpoint
* refactor: move position of if
* docs: add docstring
* refactor: add _save_to_state_dict from official torch
* docs: modify docstring of _save_to_state_dict
* docs: modify docstring
* feat: add unittest
* feat: add DataParallel to unittest
* fix: a bug when model has batchnorm
* docs: update docstring