protected static function _getDateString($value)
    {
        $formatted = '';
        if (isset($value['year'], $value['month'], $value['day']) &&
            (is_numeric($value['year']) && is_numeric($value['month']) && is_numeric($value['day']))
        ) {
            $formatted .= sprintf('%d-%02d-%02d ', $value['year'], $value['month'], $value['day']);
        }

        if (isset($value['hour'])) {
            if (isset($value['meridian']) && (int)$value['hour'] === 12) {
                $value['hour'] = 0;
            }
            if (isset($value['meridian'])) {
                $value['hour'] = strtolower($value['meridian']) === 'am' ? $value['hour'] : $value['hour'] + 12;
            }
            $value += ['minute' => 0, 'second' => 0];
            if (is_numeric($value['hour']) && is_numeric($value['minute']) && is_numeric($value['second'])) {
                $formatted .= sprintf('%02d:%02d:%02d', $value['hour'], $value['minute'], $value['second']);
            }
        }

        return trim($formatted);
    }