Problem 7.6

Using the two functions above, write a function day_add () that helps answer questions like

**Today is Wednesday. I leave for a vacation in 19 days time. What day will that be?" So the

function must take a day name and a delta argument - the number of days to add-and

should return the resulting day name:

• day_add("Monday", 4) should return "Friday"

• day_add("Tuesday", 0) should return "Tuesday"

• day_add("Tuesday", 14) should return "Tuesday"

• day_add("Sunday", 100) should return "Tuesday"