/**
* Return the expiration date of the user account.
*
* @return DateTime|null
*/
public function expirationDate()
{
$accountExpiry = $this->getAccountExpiry();
if ($accountExpiry == 0 || $accountExpiry == $this->getSchema()->neverExpiresDate()) {
return;
}
$unixTime = Utilities::convertWindowsTimeToUnixTime($accountExpiry);
return new DateTime(date($this->dateFormat, $unixTime));
}