* tmp commit

* add unittest for basedataset

* fix lint

* resolve all comments

* update

* update

* update

* update

* update

* update

* update

* resolve comments

* resolve comments

* update

* resolve comments

* resolve comments

* Add the unittest of registry

* improve the format

* fix the test_repr

* refactor the test_init

* add the copyright for tests directory

* add more unit tests

* fix error

* add unit tests for _search_child and _get_root_registry

* build_from_cfg supports dict, ConfictDict and Config

* improve docstring