new_contents: class NumArray(object):
  
      def __init__(self, nums):
          """
          :type nums: List[int]
          """
          
          self._sums = [0]
          total      = 0
          
          for num in nums:
              total += num
              
              self._sums.append(total)
  
      def sumRange(self, i, j):
          """
          :type i: int
          :type j: int
          :rtype: int
          """
          return self._sums[j + 1] - self._sums[i]
  
  
  # Your NumArray object will be instantiated and called as such:
  # obj = NumArray(nums)
  # param_1 = obj.sumRange(i,j)
  
subject: Create solution.py