What's Changed
* Fix invalid return type for user and monthsummary by DCSBL in https://github.com/DCSBL/python-frank-energie/pull/37
* Add query to get previous, current and upcoming invoice information by DCSBL in https://github.com/DCSBL/python-frank-energie/pull/38
* Add ExpectedCosts property to MonthSummary by DCSBL in https://github.com/DCSBL/python-frank-energie/pull/39
* Add tests for frank_energie by DCSBL in https://github.com/DCSBL/python-frank-energie/pull/40
* Remove mosts flake8 ignores and fix issues by DCSBL in https://github.com/DCSBL/python-frank-energie/pull/41
* Use Dataclass for 'prices' request (streamline code) by DCSBL in https://github.com/DCSBL/python-frank-energie/pull/42
**Full Changelog**: https://github.com/DCSBL/python-frank-energie/compare/3.1.0...4.0.0