'sum of elements nums[i..j], inclusive.
:type i: int
:type j: int
:rtype: int'

def sumRange(self, i, j):

    def sumRangeHelper(root, start, end):
        if ((not root) or (root.start > end) or (root.end < start)):
            return 0
        if ((root.start >= start) and (root.end <= end)):
            return root.sum
        return (sumRangeHelper(root.left, start, end) + sumRangeHelper(root.right, start, end))
    return sumRangeHelper(self.__root, i, j)
