public static function delete_evidence($evidenceorid) {
        $evidence = $evidenceorid;
        if (!is_object($evidence)) {
            $evidence = new evidence($evidenceorid);
        }

        $uc = new user_competency($evidence->get('usercompetencyid'));
        if (!evidence::can_delete_user($uc->get('userid'))) {
            throw new required_capability_exception($uc->get_context(), 'moodle/competency:evidencedelete', 'nopermissions', '');
        }

        return $evidence->delete();
    }