Opencart How to display cart amount in cart?

Question

PHP

On the opencart 3 cart page, I need to display the cart amount using a variable from the cart.php controller, then I want to manipulate it, namely, divide by 1000 to calculate the number of gifts, but this is not so important, the problem is that, I already tried a hundred times to display my variable, but it is always empty. I tried this: it $data['privet'] = $this->cart->getSubTotal();returns an empty value, then I spied on how the amount of goods in the basket is displayed, {{ product.total }I try to display it for the sake of experiment, but to no avail, an empty value is displayed, I also tried to pass any string to a variable and display it to understand whether it works at all or not, but nothing output, empty string:$data['privet'] = 'hello';. I tried to rearrange this variable in different places in the cart.php controller file, but it didn’t work (I can’t understand what the problem is because I displayed the cost of the cart in the header, $data['privet'] = $this->cart->getSubTotal();this design in the controller and {{ privet }}in the template was enough, everything works properly, but in no basket.