Goal: Build user$-$friendly error messages on exceptions.

Assignment: Three variables, price, tax and discount, supposedly hold strings of digits, suitable for converting to floats. Write code that converts them and displays the total cost $($price $*(1+$ tax$)-$ discount$),$ rounded to the second decimal digit. However, if any variable fails to convert, display a string "Failed to convert value$($s$)$: $"$ followed by the names of the variable$($s$)$ that failed, separated by space. The variables should be sorted as price, tax and discount.

If in order the variables were $"$Hi$","0\mathrm{.}09","1$:$99",$ the output would be Failed to convert value$($s$)$: price discount.

python