# File karel/tk_robot_world.rb, line 210
  def remove_beeper(street, avenue)
        # """Remove a single beeper from this corner. An exception will be raised if there are none"""
        @beepers.synchronize do
        sleep(@@delay / 200.0)
        place = [street, avenue]
        howMany = @beepers[place]
        if howMany > 0 
            howMany -= 1
            if howMany == 0 
                @beepers.delete(place)
                if $window 
                    $window.delete_beeper(place)
                end
            else
                @beepers[place] = howMany
                if $window
                    $window.delete_beeper(place)
                    $window.place_beeper(street, avenue, howMany)
                end
            end
        elsif howMany == INFINITY 
            @@beeper_control.signal
            return
        else 
           @@beeper_control.signal
             raise NoBeepers.new("(" + street.to_s + ", " + avenue.to_s + ")")
        end
        @@beeper_control.signal
        end
  end