code: def process_event(self, c):
          
          if c == "":
              sys.exit()
          elif c in key_directions:
              self.move_entity(self.player, *vscale(self.player.speed, key_directions[c]))
          else:
              return "try arrow keys, w, a, s, d, or ctrl-D (you pressed %r)" % c
          return self.tick()
docs: Returns a message from tick() to be displayed if game is over