def main(): """creates an instance of Airport and tests all the functions """ airport = Airport('Vancouver Regional Airport', 4) cap = CapacityObserver(airport) air = AirplaneObserver(airport) airport.attatch_observer(air) airport.attatch_observer(cap) airport.land_airplane('A0001') airport.land_airplane('A0002') airport.land_airplane('B0011') airport.land_airplane('B0012') airport.set_max_capacity(15) print('%s current maximum capacity is %s' % (airport.get_airport_name(), airport.get_max_capacity())) airport.set_max_capacity(8) airport.depart_airplane('B0012') airport.depart_airplane('B0011') airport.depart_airplane('A0002') airport.depart_airplane('A0001') print(str(airport))