Range sums with a prefix table

Many questions of the form "what is the total of items i to j" can be answered from one precomputed table. Build prefix where prefix[0] is 0 and prefix[i] is the sum of the first i items. Then the sum of items from position i up to and including j is prefix[j + 1] - prefix[i].

Write range_sums(nums, queries) where each query is a tuple (i, j) with 0 <= i <= j < len(nums). Return the list of answers. The point is to build the prefix table once rather than re-add the items for every query.

range_sums([2, 4, 6, 8], [(0, 1), (1, 3), (2, 2)])  ->  [6, 18, 6]

def range_sums(nums, queries):
    ...