public function cleanCartAddress($address) {
    $address = (array) $address;

    $address = $this->cleanAddress($address);

    if (isset($address['customer_address_id'])) {
      $address['customer_address_id'] = (int) $address['customer_address_id'];
    }

    // Never send address_id in API request, it confuses Magento.
    if (isset($address['address_id'])) {
      unset($address['address_id']);
    }

    return $address;
  }