public bool Equals(MusicBrainzId other)
 {
     if(ReferenceEquals(null, other))
     {
         return false;
     }
     if(ReferenceEquals(this, other))
     {
         return true;
     }
     return Equals(other.Mbid, Mbid);
 }
 public void SetUp()
 {
     _musicBrainzId = new MusicBrainzId("0004006f-14a0-4d3e-ab7c-073ecf8dbf77");
     _expectedMapping = new Mapping
     {
         SevenDigital = new SevenDigitalId(12345),
         MusicBrainz = _musicBrainzId
     };
     _loadedList = new List<IMapping>
     {
         _expectedMapping
     };
     _subject = new Repository(_loadedList);
 }