GitLab

* add label propagation module

* fix prev bug in example

* add dgn

* fix linting and doc issues

* update label propagation & dgn

* update label propagation & dgn

* update example

* fix unit test

* fix agg heritage issue

* fix agg issue

* fix lint

* fix idx

* fix lp gpu issue

* Update

* Update
Co-authored-by: mufeili <mufeili1996@gmail.com>