写一段python代码，实现快速排序
快速排序
def quick_sort(arr): if len(arr) <= 1: return arr else: pivot = arr[0] left = [x for x in arr[1:] if x < pivot] right = [x for x in arr[1:] if x >= pivot] return quick_sort(left) + [pivot] + quick_sort(right)
def quick_sort(arr): if len(arr) <= 1: return arr else: pivot = arr[0] left = [x for x in arr[1:] if x < pivot] right = [x for x in arr[1:] if x >= pivot] return quick_sort(left) + [pivot] + quick_sort(right)