code: public static BendableScore ofSoft(int hardLevelsSize, int softLevelsSize, int softLevel, int softScore) {
          int[] softScores = new int[softLevelsSize];
          softScores[softLevel] = softScore;
          return new BendableScore(0, new int[hardLevelsSize], softScores);
      }
docs: Creates a new {@link BendableScore}.
  @param hardLevelsSize at least 0
  @param softLevelsSize at least 0
  @param softLevel at least 0, less than softLevelsSize
  @param softScore any
  @return never null