public static function formatDate(\DateTimeInterface $dateTime, $format)
    {
        $phpFormats = array(
            self::DATE => "Y-m-d",
            self::DATE_AND_TIME => 'Y-m-d\TH:i:s\Z',
        );
        $phpFormat = $phpFormats[$format];

        return $dateTime->format($phpFormat);
    }