[LearnException] 
Non-strictly casts to integer:  (8448)
/mnt/data/www/evan/vhost/public/evan/bitrix/modules/learning/classes/general/clearnlessontree.php:251
#0: CLearnLessonTree->EnsureStrictlyCastableToInt(boolean)
	/mnt/data/www/evan/vhost/public/evan/bitrix/modules/learning/classes/general/clearnlessontree.php:24
#1: CLearnLessonTree->__construct(boolean, array, array, boolean, array)
	/mnt/data/www/evan/vhost/public/evan/bitrix/modules/learning/classes/general/clearnlesson.php:1874
#2: CLearnLesson::GetTree(boolean, array, array, boolean, array)
	/mnt/data/www/evan/vhost/public/evan/bitrix/modules/learning/classes/general/course.php:430
#3: CCourse::GetCourseContent(integer, array)
	/mnt/data/www/evan/vhost/public/evan/include/ajax/education/rollCancel.php:20