public class NumArray

    {

        List<int> list = new List<int>();

        public NumArray(int[] nums)

        {

            var sum = ;

            for (int i = ; i < nums.Length; i++)

            {

                sum += nums[i];

                list.Add(sum);

            }

        }

        public int SumRange(int i, int j)

        {

            if (i == )

            {

                return list[j];

            }

            else

            {

                return list[j] - list[i - ];

            }

        }

    }

/**

 * Your NumArray object will be instantiated and called as such:

 * NumArray obj = new NumArray(nums);

 * int param_1 = obj.SumRange(i,j);

 */

 from itertools import accumulate

 class NumArray:

     def __init__(self, nums: List[int]):

         self.dp = list(accumulate(nums))

     def sumRange(self, i: int, j: int) -> int:

         if i == :

             return self.dp[j]

         else:

             return self.dp[j] - self.dp[i-]