Problem 2: Senior Citizen Health Care
Often real-world functions requires input to be validated. In this problem, the only valid years
are 1977, 1978, . . . , 1997. The year, for example, 1976, is not valid. Python allows for a single
Boolean expression for intervals. Suppose you’re given an interval [l, u] where l <= u. The image
below shows valid values (green line and filled circles) and invalid values (black lines).