Practical4
culture_density.py： The feedback suggests a wrong explanation for "the number of days required to exceed 90% density" because I had started with day=1 to represent the first day, but forgot to exclude it in the holiday calculation. So I subtracted two (the first day and the last day) from the number of holidays instead of the previous one (the last day).
Practical6
average_day.py： The feedback said that I had "encoded the pie chart data in the lists" because I had entered lists directly for the pie chart. I modified it by extracting lists of keys and values from the dictionary I had previously created to ensure that the pie chart would change as the dictionary changed.
city_size.py： I didn't print two sorted lists of city sizes according to the feedback, so I added two print statements to output sorted lists of city sizes in the UK and China.