use_method()

It is used in the case you need to call some data on the module with the help of jQuery/Ajax or if you need to open a page.

This method is used in "Admin Area > Order Detail > Core" and "Client Area > Order Detail" page.

In the /pages/ac-order-detail.php and /pages/order-detail.php files, in case you send below parameters to the url address in $controller_link variable with GET or POST method, the parameters are sent to the use_method() function which is in the class.

Thus, the data you have added in use_method function are printed to the screen.

public function use_method($method=''){
    if($method == "apply_changes") return $this->ac_edit_order_params();
    return true;
}