Msgbox widget child objects created but LV_ASSERT_MALLOC(obj); called for parent

General discussion
1

While learning how to create new widget I was looking in to msgbox widget code and noticed that after child objects created for some reason called LV_ASSERT_MALLOC(obj); where parent obj passed as parameter, but not pointer to child object that was just created.

See:

lines: 129, 130

    mbox->content = lv_obj_class_create_obj(&lv_msgbox_content_class, obj);
    LV_ASSERT_MALLOC(obj);

lines: 144, 145

    mbox->header = lv_obj_class_create_obj(&lv_msgbox_header_class, obj);
    LV_ASSERT_MALLOC(obj);

…and many other places in this file where similar appears.

Why so?? obj is a parent object that was created long before and successful allocation was checked.
Shouldn’t it be like:

    mbox->header = lv_obj_class_create_obj(&lv_msgbox_header_class, obj);
    LV_ASSERT_MALLOC(mbox->header);

Below there is usually correct check for null pointer to child object. Just there will not be any output done by LV_ASSERT_MALLOC for obj. Right?