docs: @Nullable
      @CardBrand
      public static String asCardBrand(@Nullable String possibleCardType) {
          if (possibleCardType == null || TextUtils.isEmpty(possibleCardType.trim())) {
              return null;
          }
  
          if (Card.AMERICAN_EXPRESS.equalsIgnoreCase(possibleCardType)) {
              return Card.AMERICAN_EXPRESS;
          } else if (Card.MASTERCARD.equalsIgnoreCase(possibleCardType)) {
              return Card.MASTERCARD;
          } else if (Card.DINERS_CLUB.equalsIgnoreCase(possibleCardType)) {
              return Card.DINERS_CLUB;
          } else if (Card.DISCOVER.equalsIgnoreCase(possibleCardType)) {
              return Card.DISCOVER;
          } else if (Card.JCB.equalsIgnoreCase(possibleCardType)) {
              return Card.JCB;
          } else if (Card.VISA.equalsIgnoreCase(possibleCardType)) {
              return Card.VISA;
          } else if (Card.UNIONPAY.equalsIgnoreCase(possibleCardType)) {
              return Card.UNIONPAY;
          } else {
              return Card.UNKNOWN;
          }
      }