import EventObserver

# class object MUST inherit Observer object if you use it within class
class Room(Observer):
    def __init__(self):
        print("Room is ready.")
        Observer.__init__(self)  # DON'T FORGET THIS
        # observer can be declared already in class init method with following line
        # this.observe('someone sneezed', this.someone_sneezed)

    def someone_arrived(self, who):
        print("{} has arrived!".format(who))
        
    def someone_sneezed(self, who):
        print("{} has just sneezed!".format(who))


# Observe for specific event
room = Room()
room.observe('arrived', room.someone_arrived)
room.observe('sneezed', room.someone_arrived)

# Fire some events
Event('left', 'John')       # no events are attached to event "someone left" 
Event('arrived', 'Lenard')  # will output "Lenard has arrived!"
Event('sneezed', 'Jenny')   # will output "Jenny has just sneezed!"

# Remove known event
room.forget('arrived')

# no events based on 'someone arrived' will be fired
'''