function addLesson($lesson_title, $lesson_parent_id = 0) { $lesson_object = new Lesson(); $lesson_object->setTitle($lesson_title)->setIsRoot(!$lesson_parent_id)->save(); if ($lesson_parent_id) { $lesson_parent_object = new LessonParent(); $lesson_parent_object->setLessonId($lesson_object->getId())->setParentId($lesson_parent_id)->save(); } return $lesson_object->getId(); }