Usage:
<pre>new DatePeriod(string $period);</pre>
<pre>new DatePeriod(DateTime|string $startDate, DateTime|string $endDate);</pre>
where $period is a string like '2020-01-25 - 2020-02-10' (or '2020-01-25 -
2020-01-25' - even if the dates are the same).
Usage:
<pre>new TimePeriod(string $period);</pre>
<pre>new TimePeriod(DateTime|string $startTime, DateTime|string $endTime);</pre>
where $period is a string like '08:00 - 14:00'.