def validate_payment_issuer!(options)
      if options[:payment_method] == PaymentMethod::IDEAL || options[:payment_method] == PaymentMethod::IDEAL_PROCESSING
        unless Ideal::ISSUERS.include?(options[:payment_issuer])
          raise ArgumentError, "Invalid payment issuer: #{options[:payment_issuer]}"
        end
      end
    end
def validate_payment_issuer!(options)
      if options[:payment_method] == PaymentMethod::IDEAL || options[:payment_method] == PaymentMethod::IDEAL_PROCESSING
        unless Ideal::ISSUERS.include?(options[:payment_issuer])
          raise ArgumentError, "Invalid payment issuer: #{options[:payment_issuer]}"
        end
      end
    end
Validate the payment issuer when iDEAL is selected as payment method.