public function createBuyer(
        $email_address,
        $card_href,
        $meta = null,
        $name = null)
    {
        $customer = $this->customers->create(array(
            'email' => $email_address,
            'meta' => $meta,
            'name' => $name
            ));
        $card = Card::get($card_href);
        $card->associateToCustomer($customer);
        return $customer;
    }