public static Artist CreateOrLoadArtist(IRepository<Artist> artists, ArtistDetails artistDetails)
        {
            Artist artist = artists.Get(artistDetails.ID);
            if (artist != null)
            {
                return artist;
            }

            Artist newArtist = new Artist()
            {
                Name = artistDetails.Name,
                Country = artistDetails.Country,
                DateOfBirth = artistDetails.DateOfBirth
            };

            artists.Add(newArtist);

            return newArtist;
        }
        private static ArtistDetails ConvertToArtistDetails(ArtistModel artistModel)
        {
            ArtistDetails artistDetails = new ArtistDetails()
            {
                ID = artistModel.ID,
                Name = artistModel.Name,
                DateOfBirth = artistModel.DateOfBirth,
                Country = artistModel.Country
            };

            return artistDetails;
        }
 private static void AddSongs(
     ArtistDetails artistWithId2,
     ArtistDetails artistWithId3,
     SongsDataClient songsJsonDataClient,
     SongsDataClient songsXmlDataClient)
 {
     songsJsonDataClient.AddSong("Song 1", 2009, "Hip-Hop",
         new List<ArtistDetails>() { artistWithId2, artistWithId3 }, new List<AlbumDetails>());
     songsJsonDataClient.AddSong("Song 2", 2011, "House",
         new List<ArtistDetails>() { artistWithId3 }, new List<AlbumDetails>());
     songsXmlDataClient.AddSong("Song 3", 2009, "Trance",
         new List<ArtistDetails>() { artistWithId2 }, new List<AlbumDetails>());
     songsXmlDataClient.AddSong("Song 4", 2009, "Pop",
         new List<ArtistDetails>() { artistWithId3 }, new List<AlbumDetails>());
     songsXmlDataClient.AddSong("Song 5", 2009, "Rap",
         new List<ArtistDetails>() { artistWithId2 }, new List<AlbumDetails>());
 }