- If this function returns True then no functions that modify the
- database (:meth:`add_message`, :meth:`add_tag`,
- :meth:`Directory.set_mtime`, etc.) will work unless :meth:`upgrade`
- is called successfully first.
+ If this function returns `True` then no functions that modify the
+ database (:meth:`add_message`,
+ :meth:`Message.add_tag`, :meth:`Directory.set_mtime`,
+ etc.) will work unless :meth:`upgrade` is called successfully first.