python, please explain everything

(15 points) Write a while loop that will go through each element of a tuple and add every fourth item to a new list. The first item to be added from the old list will be in position 1. Ex: oldTup=(1,2,3,4,5,6,7) newlist would contain (2,6) tup= (0,23, 5, 17, 31, 16, 99, 45, 22, 86,7,16, ..., 64) The exact number of items is unknown but this is a sample of the tuple to be processed