How can a custom icon be used in an image menu item?

I can create menu items with icons:

new = gtk.ImageMenuItem(gtk.STOCK_NEW, 'New')

but how can I use a custom icon -开发者_Python百科 from a file?

http://library.gnome.org/devel/pygtk/stable/class-gtkimagemenuitem.html#method-gtkimagemenuitem--set-image

img = gtk.Image()
img.set_from_file(filename)
new = gtk.ImageMenuItem(gtk.STOCK_NEW, 'New')
new.set_image(img)

For me the following code worked:

img = gtk.Image()
img.set_from_stock(gtk.STOCK_NEW, 1)
item = gtk.ImageMenuItem('New')
item.set_image(img)
menu.append(item)