The use of `enumerate` in some of the general examples doesn't seem right to me. Take, for instance, the part of the general solution: for r, _ in enumera

The use of `enumerate` in some of the general examples doesn't seem right to me. Take, for instance, the part of the general solution: for r, _ in enumerate(RESOURCES): solver.Add(sum(DATA[u][r] * units[u] for u, _ in enumerate(units)) <= RESOURCES[r]) the author is basically using enumerate to get the indices from the list, and nothing else. It seems like it would be much better to either do: for r, resource in enumerate(RESOURCES): solver.Add(sum(DATA[u][r] * unit for u, unit in enumerate(units)) <= resource) `enumerate` is supposed to return both the index and the value, so indexing the list you just passed to `enumerate` seems like bad form. Is there some reason not to do it this way?