commented Refactoring: Simplified some code by using the `to_list` function. (#10678) ### Summary We have the method `to_list` in keras. Let's use it to make the codebase simpler! ### Related Issues ### PR Overview - [ ] This PR requires new unit tests [y/n] (make sure tests are included) - [ ] This PR requires to update the documentation [y/n] (make sure the docs are up-to-date) - [x] This PR is backwards compatible [y/n] - [ ] This PR changes the current API [y/n] (all API changes need to be approved by fchollet)