docs: def _highlight_surrounding_scopes(self, block):
          """
          Highlights the scopes surrounding the current fold scope.
  
          :param block: Block that starts the current fold scope.
          """
          scope = FoldScope(block)
          if (self._current_scope is None or
                  self._current_scope.get_range() != scope.get_range()):
              self._current_scope = scope
              self._clear_scope_decos()
              # highlight surrounding parent scopes with a darker color
              start, end = scope.get_range()
              if not TextBlockHelper.is_collapsed(block):
                  self._add_scope_decorations(block, start, end)