function addCartItem($name, $quantity, $totalAmount, $description = "") {

		if (count($this->cart) >= 2) {
			throw new Exception("This version of banks's API supports only up to 2 cart items in single payment, you can't add any more items.");
		}

		if (!is_numeric($quantity) or $quantity < 1) {
			throw new Exception("Invalid quantity: $quantity. It must be numeric and >= 1");
		}

		$name = trim(Strings::shorten($name, 20, "", true, true));
		$description = trim(Strings::shorten($description, 40, "", true, true));

		$this->cart[] = array(
			"name" => $name,
			"quantity" => $quantity,
			"amount" => intval(round($totalAmount)),
			"description" => $description
		);

		return $this;
	}