def quick_sort(nums):

     if not nums:

         return []

     else:

         # 这里取第0个数为基点

         flag = nums[0]

         # 小于flag 的放到左边

         left = quick_sort([ln for ln in nums[1:] if ln <= flag])

         # 大于flag的放到右边

         right = quick_sort([rn for rn in nums[1:] if rn > flag])

         # 最后相加返回结果，别忘了flag

         return left + [flag] + right

 a = [0, 6, 5, 4, 3, 1, 2, 3, 0]

 print(quick_sort(a))