public NewSongCheckResultContract(DuplicateEntryResultContract<SongMatchProperty>[] matches, NicoTitleParseResult titleParseResult, ContentLanguagePreference languagePreference)
        {
            this.Matches = matches;

            if (titleParseResult != null) {
                this.Artists = titleParseResult.ArtistNames.Where(a => a != null).Select(a => new ArtistContract(a, languagePreference)).ToArray();
                this.SongType = titleParseResult.SongType;
                this.Title = titleParseResult.Title;
            }
        }
		public NewSongCheckResultContract() {
			Matches = new DuplicateEntryResultContract<SongMatchProperty>[] { };
		}