public IEnumerable<DalMark> GetAllSongMarksBySongId(int key)
{
ICollection<Mark> collection = new Collection<Mark>();
Song ormSong = _context.Set<Song>().FirstOrDefault(song => song.Id == key);
foreach (Marks marks in ormSong.Marks)
{
collection.Add(marks.Mark);
}
return collection.ToDalMark();
}
