private function serializeCard()
 {
     return ['rank' => $this->card->getRank(), 'suit' => $this->card->getSuit()];
 }
 private function serializeCard(Card $card)
 {
     return ['rank' => $card->getRank(), 'suit' => $card->getSuit()];
 }
 /**
  * @return array
  */
 public function toArray()
 {
     return ['card' => ['rank' => $this->card->getRank(), 'suit' => $this->card->getSuit()]];
 }