quick sort descending order algorithm python

1def partition(array, begin, end):
2    pivot_idx = begin
3    for i in xrange(begin+1, end+1):
4        if array[i] <= array[begin]:
5            pivot_idx += 1
6            array[i], array[pivot_idx] = array[pivot_idx], array[i]
7    array[pivot_idx], array[begin] = array[begin], array[pivot_idx]
8    return pivot_idx
9
10def quick_sort_recursion(array, begin, end):
11    if begin >= end:
12        return
13    pivot_idx = partition(array, begin, end)
14    quick_sort_recursion(array, begin, pivot_idx-1)
15    quick_sort_recursion(array, pivot_idx+1, end)
16
17def quick_sort(array, begin=0, end=None):
18    if end is None:
19        end = len(array) - 1
20    
21    return quick_sort_recursion(array, begin, end)

1NameError: name 'xrange' is not defined