Data shift Lesson-2 activity_5

[whplh]

In Lesson-2 activity_5 the create_groups() function causes a shift in the data with the used dataset.
The first iso_week of the sample dataset contains only 2 values for friday and saturday.
This can happen every year at the beginning and the end of iso_weeks in any dataset.
How to handle missing/shifted data here?

[whplh]

in the line: "if len(sample)==group_size" the length of sample will always be 7 since the data was sliced with the default group_size, which is 7 and thus causing the shift at the beginning of the year.