human
Solve the following python programming problem given the following code:
def main() : 
    global keyboard, scroller, old_ij, old_cell, old_highlighted_color 
    from cocos.director import director 
    director.init (width = 600, height = 300, autoscale = False, resizable = True) 
    car_layer = layer.ScrollableLayer () 
    car = cocos.sprite.Sprite ('car.png') 
    car_layer.add (car) 
    car.position = (200, 100) 
    car.max_forward_speed = 200 
    car.max_reverse_speed = (- 100) 
    car.do (DriveCar ()) 
    scroller = layer.ScrollingManager () 
    map_loaded = tiles.load ('hexmap.tmx') 
    test_layer = map_loaded ['tile_layer_1'] 
    tint_green_hexmap_borders (test_layer) 
    scroller.add (test_layer) 
    scroller.add (car_layer) 
    old_ij = 'nonexist' 
    old_highlighted_color = None 
    old_cell = None 
    main_scene = cocos.scene.Scene (scroller) 
    keyboard = key.KeyStateHandler () 
    director.window.push_handlers (keyboard) 
    def on_key_press(key, modifier) : 
        if (key == pyglet.window.key.Z) : 
            if (scroller.scale == 0.75) : 
                scroller.do (actions.ScaleTo (1, 2)) 
else : 
                scroller.do (actions.ScaleTo (0.75, 2)) 
else : 
            if (key == pyglet.window.key.D) : 
                test_layer.set_debug (True) 
else : 
                if (key == pyglet.window.key.Q) : 
                    tint_red_hexmap_borders (test_layer) 
director.window.push_handlers (on_key_press) 
    def on_mouse_motion(x, y, dx, dy) : 
        global scroller, old_ij, old_cell, old_highlighted_color 
        (vx, vy) = scroller.pixel_from_screen (x, y) 
        ij = test_layer.get_key_at_pixel (vx, vy) 
        if (ij == old_ij) : 
            return 
if old_cell : 
            (p, q) = old_ij 
            if (old_highlighted_color is None) : 
                test_layer.set_cell_color (p, q, (255, 255, 255)) 
                del old_cell.properties ['color4'] 
else : 
                test_layer.set_cell_color (p, q, old_highlighted_color [: 3]) 
old_ij = ij 
        (i, j) = ij 
        print (i, j) 
        old_cell =...

    
    

    Fix the buggy line: director.window.push_handlers (old_ij)
assistant
#Here is Python program to fix the buggy line: director.

director.window.push_handlers (def on_mouse_motion()