from random import choice

def quick_sort(a_list):
    if len(a_list) <= 1:
        return a_list
    pivot = choice(range(len(a_list)))
    return quick_sort([i for i in a_list[:pivot] + a_list[pivot+1:]
                       if i < a_list[pivot]]) + [a_list[pivot]] + \
           quick_sort([i for i in a_list[:pivot] + a_list[pivot+1:]
                       if i >= a_list[pivot]])