`OpenEndedModule` is a child class of `OpenEndedChild`. The method `get_score` of `CombinedOpenEndedV1Module` uses `all_scores` of `OpenEndedChild` to [retrieve scores](https://github.com/waheedahmed/edx-platform/blob/9b56fe687fcde7ff19e681504e49d81285799ae8/common/lib/xmodule/xmodule/open_ended_grading_classes/combined_open_ended_modulev1.py#L1018-L1036) of all attempts of all `task_states`.

This `all_scores()` method in `OpenEndedModule` instead of simply picking the value from the attempt dictionary as [is done](https://github.com/waheedahmed/edx-platform/blob/9b56fe687fcde7ff19e681504e49d81285799ae8/common/lib/xmodule/xmodule/open_ended_grading_classes/openendedchild.py#L197-L207) in `OpenEndedChild` uses `self.score_for_attempt()`