}

  @Override
  public boolean equals(@Nullable Object obj) {
    if (obj == this) {
      return true;
    }
    if (obj instanceof FunctionalEquivalence) {
      FunctionalEquivalence<?, ?> that = (FunctionalEquivalence<?, ?>) obj;
      return function.equals(that.function) && resultEquivalence.equals(that.resultEquivalence);
    }
    return false;
  }

  @Override