* Add `regta_period.AbstractPeriod`
* `.get_next`
* `.get_interval`
* Add `regta_period.Period`
* `.every`
* `.seconds`
* `.minutes`
* `.hours`
* `.days`
* `.hourly`
* `.daily`
* `.on`
* `.monday`
* `.tuesday`
* `.wednesday`
* `.thursday`
* `.friday`
* `.saturday`
* `.sunday`
* `.weekdays`
* `.weekends`
* `.at`
* `.by`
* `.get_next`
* `.get_interval`
* `.AND`
* `.OR`
* `.__add__`
* `.__or__`
* `.__repr__`
* Add `regta_period.PeriodAggregation`
* `.get_next`
* `.get_interval`
* `.OR`
* `.__or__`
* `.__dir__`
* `.__getattr__`
* `.__repr__`
* Add `regta_period.Weekdays`
* `.get`