docs: def restore_comments(self, restore_data):
          """Restore comment styles and data
          """
          for start, end, styles, items in restore_data:
              log.debug("range: %d-%d" % (start, end))
              self.style[start:end] = styles
              for i in range(start, end):
                  rawindex, comment = items[i]
                  if comment:
                      log.debug("  restoring comment: rawindex=%d, '%s'" % (rawindex, comment))
                      self.rawdata.extra.comments[rawindex] = comment
                  else:
                      # no comment in original data, remove any if exists
                      try:
                          del self.rawdata.extra.comments[rawindex]
                          log.debug("  no comment in original data, removed comment in current data at rawindex=%d" % rawindex)
                      except KeyError:
                          log.debug("  no comment in original data or current data at rawindex=%d" % rawindex)
                          pass