code: def _decorate_block(self, start, end):
          
          color = self._get_scope_highlight_color()
          draw_order = DRAW_ORDERS.get('codefolding')
          d = TextDecoration(self.editor.document(), start_line=start,
                             end_line=end+1, draw_order=draw_order)
          d.set_background(color)
          d.set_full_width(True, clear=False)
          self.editor.decorations.add(d)
          self._scope_decos.append(d)
docs: Create a decoration and add it to the editor.
  
          Args:
              start (int) start line of the decoration
              end (int) end line of the decoration