A small chain has shops in different countries. Each shop reports its takings in its own currency. The takings arrive as a grid: one row per day, one column per shop.
rates[s] is how many pounds one unit of shop s's currency is worth. It applies to that shop's takings on every day.
Task: write daily_takings(sales, rates). Convert every value to pounds, then return the chain's total in pounds for each day, as a list in day order. Round each total to 2 decimal places.