So now the existing TimeSeries and ArrayTimeSeries must be reparented. Note that some methods in ArrayTimeSeries might have been inherited from Timeseries. Some of this code may have to be defined in one of the above ABCs (its perfectly fine for ABCs to not have all methods @abstractmethoded).
Make sure that all tests you had working earlier still work. These tests will ensure that this refactoring effort on your part does not break anything.
Note that you'll have different constructors here: thats ok. The constructors are not (yet) part of any common interface.
From the Project Spec 5: