# File default/guard.rb, line 23
    def follow_edge()
        while next_to_a_beeper?() 
            if front_is_clear?() 
                move()
            else 
                pick_beeper()
            end
        end
        if not front_is_clear?() 
            if any_beepers_in_beeper_bag?() 
                put_beeper()
            else 
                back_up()
            end
        else 
            back_up()
        end
    end