equals method

Implementation

@override
bool equals(HandInterface other) {
  if (other is! OrphanHand) return false;
  if (_cards.length != other.length) return false;

  for (int i = 0; i < _cards.length; i += 1) {
    if (_cards[i] != other.cardAt(i)) return false;
  }
  return true;
}