public async Task <IEnumerable <TrackDto> > GetTopTracksAsync(int?count)
        {
            if (count == null)
            {
                count = 50;
            }
            var spec   = new TopTracksSpecification(count);
            var tracks = await _trackRepository.ListAsync(spec);

            return(tracks.Select(t => new TrackDto
            {
                TrackId = t.Id,
                Name = t.Name,
                Artist = t.Album.Artist.Name,
                ArtistId = t.Album.ArtistId,
                Album = t.Album.Title,
                AlbumId = t.Album.Id,
                Score = t.Score,
                FromCache = t.FromCache
            }));
        }