python range reverse
When you call range() with three arguments, you can choose not only
where the series of numbers will start and stop but also how big the
difference will be between one number and the next.
range(start, stop, step)
If your 'step' is negative and 'start' is bigger than 'stop', then
you move through a series of decreasing numbers.
for i in range(10,0,-1):
print(i, end=' ')
# Output: 10 9 8 7 6 5 4 3 2 1