public function search_other_users($search = '', $searchanywhere = false, $page = 0, $perpage = 25, $returnexactcount = false) {
        global $DB, $CFG;

        list($ufields, $params, $wherecondition) = $this->get_basic_search_conditions($search, $searchanywhere);

        $fields      = 'SELECT ' . $ufields;
        $countfields = 'SELECT COUNT(u.id)';
        $sql   = " FROM {user} u
              LEFT JOIN {role_assignments} ra ON (ra.userid = u.id AND ra.contextid = :contextid)
                  WHERE $wherecondition
                    AND ra.id IS NULL";
        $params['contextid'] = $this->context->id;

        return $this->execute_search_queries($search, $fields, $countfields, $sql, $params, $page, $perpage, 0, $returnexactcount);
    }