As a result of this ticket https://tracker.moodle.org/browse/MDL-79907, we thought that an improvement can be made.

There are classes in grade/lib.php that can be refactored to be on their own file.

Including, but not limited to:

• graded_users_iterator
• grade_plugin_return
• grade_structure
• grade_seq
• grade_tree
• grade_helper