PayPal\Api\CreditCard::setFirstName PHP Method

    public function setFirstName($first_name)
    {
        $this->first_name = $first_name;
        return $this;
    }

 public static function createCreditCard()
 {
     $card = new CreditCard();
     $card->setType(self::$cardType);
     $card->setNumber(self::$cardNumber);
     $card->setExpireMonth(self::$expireMonth);
     $card->setExpireYear(self::$expireYear);
     $card->setCvv2(self::$cvv);
     $card->setFirstName(self::$firstName);
     $card->setLastName(self::$lastName);
     $card->setPayerId(self::$payerId);
     return $card;
 }