code: def construct_asset_path(self, asset_path, css_path, output_filename, variant=None):
          
          public_path = self.absolute_path(asset_path, os.path.dirname(css_path).replace('\\', '/'))
          if self.embeddable(public_path, variant):
              return "__EMBED__%s" % public_path
          if not posixpath.isabs(asset_path):
              asset_path = self.relative_path(public_path, output_filename)
          return asset_path
docs: Return a rewritten asset URL for a stylesheet