protected function migrateLessons()
    {
        $this->output->info('### Migrating lessons ###');
        if ($this->checkLessonsMigrationState()) {
            foreach ($this->lessons() as $lesson) {
                $lesson->showMigratingInfo($this->output,1);
                $this->migrateLesson($lesson);
            }
        }
        $this->output->info('### END OF Migrating lessons ###');
    }