My concern is with the following, which used to be functioning calls:

```php
CakeTime::daysAsSql(new DateTime('2014-03-17 00:00:00'), new DateTime('2014-03-18 20:30:00'));
CakeTime::daysAsSql('2014-03-17 00:00:00', '2014-03-18 20:30:00');
```

Both of these will fail now, but used to work.