private function findCalendar($calendarId, $calendars)
    {
        if (isset($calendars[$calendarId])) {
            return $calendars[$calendarId];
        } else {
            throw new \Exception(
                $this->translator->trans(
                    'services.calendar_manager.calendar_in_block_not_found',
                    array('%calendarId%' => $calendarId),
                    'exceptions'
                )
            );
        }
    }