Investigate the behaviour of FirstOccurrence and LastOccurence
The expected output of the index functions FirstOccurrence and LastOccurrence needs to be further investigated. FirstOccurrence call_func returns 0 for the first day. This does not match up with the output from Last Occurrence call_func that returns 1 for the first day. The output is then post process which may change the end result. Therefor, further investigation of the final output is needed to estimate if both functions are working as expected.