lib/Model/CheckoutOrder.php
public function setCartReference($cart_reference)
    {
        if (!is_null($cart_reference) && (strlen($cart_reference) > 200)) {
            throw new \InvalidArgumentException('invalid length for $cart_reference when calling CheckoutOrder., must be smaller than or equal to 200.');
        }

        $this->container['cart_reference'] = $cart_reference;

        return $this;
    }
public function setCartReference($cart_reference)
    {
        if (!is_null($cart_reference) && (strlen($cart_reference) > 200)) {
            throw new \InvalidArgumentException('invalid length for $cart_reference when calling CheckoutOrder., must be smaller than or equal to 200.');
        }

        $this->container['cart_reference'] = $cart_reference;

        return $this;
    }
Sets cart_reference
@param string $cart_reference The shopping cart reference id
@return $this