def generate_css(self, packing):
        """Generate the background offset CSS rules."""
        with open(self.css_file, "w") as css:
            css.write("/* Generated classes for django-media-bundler sprites.  "
                      "Don't edit! */\n")
            props = {
                "background-image": self.get_bundle_url() % "url('%s')",
            }
            css.write(self.make_css(None, props))
            for (left, top, box) in packing:
                props = {
                    "background-position": "%dpx %dpx" % (-left, -top),
                    "width": "%dpx" % box.width,
                    "height": "%dpx" % box.height,
                }
                css.write(self.make_css(os.path.basename(box.filename), props))
dataset/ETHPy150Open rnk/django-media-bundler/media_bundler/bundler.py/PngSpriteBundle.generate_css/swapped operands of `%`