public function get($format = self::TIMESTAMP)
{
if ($format == self::DATE_TIME) {
return $this->time;
} elseif ($format == self::TIMESTAMP) {
return $this->time->getTimestamp();
} elseif ($format == self::DATE_STRING) {
return $this->time->format('d-m-y');
} else {
throw new \InvalidArgumentException("Unknown time format '" . $format . "'");
}
}