code: def _process_value(value):
      
      if not value:
          value = _("Not set")
      # XXX: bad data, e.g. in AS Method field
      elif value == "None":
          value = _("Not set")
      # 0 is detected as the portal UID
      elif value == "0":
          pass
      elif api.is_uid(value):
          value = _get_title_or_id_from_uid(value)
      elif isinstance(value, (dict)):
          value = json.dumps(sorted(value.items()), indent=1)
      elif isinstance(value, (list, tuple)):
          value = sorted(map(_process_value, value))
          value = "; ".join(value)
      elif isinstance(value, unicode):
          value = api.safe_unicode(value).encode("utf8")
      return str(value)
docs: Convert the value into a human readable diff string