get_instance return null

Yes, I have it, and checked the chmod privileges

What I wanted to do is just load 2 lang files and use a template library

class MY_Exceptions extends CI_Exceptions
{
    public function show_404($page = '', $log_error = TRUE)
    {
        // By default we log this, but allow a dev to skip it
        if ($log_error)
        {
            log_message('error', '404 Page Not Found --> '.$page);
        }        
        
        $CI =& get_instance();        
        $CI->lang->load('error/index');        
        $CI->lang->load('pages/not_found');        

        $CI->template->title($CI->lang->line('title'))
                     ->meta('keywords', $CI->lang->line('keywords'))
                     ->meta('description', $CI->lang->line('description'))
                     ->make('errors/not_found');
        echo $CI->output->get_output();        
        exit;
    }
}

the var_dump($CI) outputs NULL



In CI2 worked perfectly.