Send errors via email

Not tried in CI2 but others had used it and it worked for them in CI2 but I cant find any code for CI3. I have now tried various examples but none worked so far, the latest code below looks to be o.k. but is giving an error 'Notice: Trying to get property of non-object' when trying to load the config but I cant figure out why.

PHP Code:

class MY_Exceptions extends CI_Exceptions {
    
    protected $CI;
    
    public function __construct()
    {
            // Assign the CodeIgniter super-object
            $this->CI =& get_instance();
    }

    public function log_exception($severity, $message, $filepath, $line)
    {

        // this allows different params for different environments
        $this->CI->config->load('email_php_errors');

        // if it's enabled
        if (config_item('email_php_errors'))
        {
            // set up email with config values
             $this->CI->load->library('email');
             $this->CI->email->from(config_item('php_error_from'));
             $this->CI->email->to(config_item('php_error_to'));

            // set up subject
            $subject = config_item('php_error_subject');
            $subject = $this->_replace_short_tags($subject, $severity, $message, $filepath, $line);
             $this->CI->email->subject($subject);

            // set up content
            $content = config_item('php_error_content');
            $content = $this->_replace_short_tags($content, $severity, $message, $filepath, $line);

            // set message and send
             $this->CI->email->message($content);
             $this->CI->email->send();
        }

        // do the rest of the codeigniter stuff
        parent::log_exception($severity, $message, $filepath, $line);
    }

    private function _replace_short_tags($content, $severity, $message, $filepath, $line)
    {
        $content = str_replace('{{severity}}', $severity, $content);
        $content = str_replace('{{message}}', $message, $content);
        $content = str_replace('{{filepath}}', $filepath, $content);
        $content = str_replace('{{line}}', $line, $content);

        return $content;
    }

}