/// <summary>
/// Applies a <see cref="BeatmapDifficulty"/> to the mod and returns a new <see cref="BeatmapDifficulty"/>
/// representing the result if the mod were applied to a fresh <see cref="BeatmapDifficulty"/> instance.
/// </summary>
private BeatmapDifficulty applyDifficulty(BeatmapDifficulty difficulty)
{
// ensure that ReadFromDifficulty doesn't pollute the values.
var newDifficulty = difficulty.Clone();
testMod.ReadFromDifficulty(difficulty);
testMod.ApplyToDifficulty(newDifficulty);
return(newDifficulty);
}