public static function GetAndStoreUsersInSession($caller) {
        $users = array();
        if (!$caller->app()->user()->getAttribute(\Puzzlout\Framework\Enums\SessionKeys::AllUsers)) {
            $manager = $caller->managers()->getDalInstance($caller->module());
            $users = $manager->selectAllUsers();

            $caller->app()->user->setAttribute(
                    \Puzzlout\Framework\Enums\SessionKeys::AllUsers, $users
            );
        } else {
            $users = $caller->app()->user->getAttribute(\Puzzlout\Framework\Enums\SessionKeys::AllUsers);
        }
        return $users;
    }