public function addPaymentMethod($paymentId, IPaymentMethod $paymentMethod)
    {
        $nameOnAccount = sprintf('%s %s', $this->firstName, $this->lastName);
        if (empty(str_replace(' ', '', $nameOnAccount))) {
            $nameOnAccount = $this->company;
        }

        $payment = new RecurringPaymentMethod($paymentMethod);
        $payment->address = $this->address;
        $payment->customerKey = $this->key;
        $payment->id = $paymentId;
        $payment->nameOnAccount = $nameOnAccount;
        return $payment;
    }