public async Task <IActionResult> Lesson(string id)
        {
            try
            {
                ILessonRepository lessonRepository = new LessonRepository( );

                var lesson = await lessonRepository.GetLessonById(id);

                return(Ok(lesson));
            }
            catch (Exception ex)
            {
                return(BadRequest(new ErrorMessage(ex)));
            }
        }