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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def pixbuf_to_cairo_gdk(pixbuf):
 """Convert from PixBuf to ImageSurface, using GDK. This method is fastest but GDK is not always available. """

    dummy_context = Context(ImageSurface(constants.FORMAT_ARGB32, 1, 1))
    gdk.gdk_cairo_set_source_pixbuf(
        dummy_context._pointer, pixbuf._pointer, 0, 0)
    return dummy_context.get_source().get_surface()