class Solution:
def runningSum(self, nums: List[int]) -> List[int]:
if nums is None or len(nums) == 0:
return nums
for i in range(1, len(nums)):
nums[i] += nums[i-1]
return nums
# def runningSum(self, nums: List[int]) -> List[int]:
# # accumulate method
# return accumulate(nums)
