+ # POST handlers
+
+ def _change_versioned_timestamps(self, cls: Any, attr_name: str) -> str:
+ """Update history timestamps for VersionedAttribute."""
+ id_ = self._params.get_int_or_none('id')
+ item = cls.by_id(self.conn, id_)
+ attr = getattr(item, attr_name)
+ for k, v in self._form_data.get_first_strings_starting('at:').items():
+ old = k[3:]
+ if old[19:] != v:
+ attr.reset_timestamp(old, f'{v}.0')
+ attr.save(self.conn)
+ cls_name = cls.__name__.lower()
+ return f'/{cls_name}_{attr_name}s?id={item.id_}'
+