'NoneType' object is not subscriptable

报错详情

TypeError                                 Traceback (most recent call last)
<ipython-input-60-ded50b25f427> in <module>
      3 print(type(nums))
      4 solution_sort  = solution_sort()
----> 5 result=solution_sort.threesum(nums)

<ipython-input-59-ab68c837c1b5> in threesum(self, nums)
      7         nums = nums.sort()
      8         for i in range(length):
----> 9             if nums[i] > 0:
     10                 return result
     11             if nums[i] == nums[i+1]:

TypeError: 'NoneType' object is not subscriptable

原因

nums = nums.sort()

列表排序之后变为NoneType object

解决方法

nums.sort()
num1 = nums[1]