public bool SetTrack(Track track, GuitarDifficulty difficulty = GuitarDifficulty.Unknown)
{
var ret = false;
if (difficulty.IsUnknown())
difficulty = this.CurrentDifficulty;
if (track.IsFileTypePro())
{
ret = SetTrack6(track, difficulty);
}
else
{
ret = SetTrack5(track, difficulty);
}
return ret;
}