}

  @Override
  protected boolean doEquivalent(F a, F b) {
    return resultEquivalence.equivalent(function.apply(a), function.apply(b));
  }

  @Override
  protected int doHash(F a) {
    return resultEquivalence.hash(function.apply(a));
  }

  @Override
  public boolean equals(@CheckForNull Object obj) {
    if (obj == this) {
      return true;
    }

  }

  @Override
  protected boolean doEquivalent(F a, F b) {
    return resultEquivalence.equivalent(function.apply(a), function.apply(b));
  }

  @Override
  protected int doHash(F a) {
    return resultEquivalence.hash(function.apply(a));
  }

  @Override
  public boolean equals(@CheckForNull Object obj) {
    if (obj == this) {
      return true;
    }