In this case, the above Query() object will be automatically freed
whenever we delete all derived objects, ie in our case:
- `del(msgs)` would also delete the parent Query (but not the parent
- Database() as that is still referenced from the variable *db* in
- which it is stored.
+ `del(msgs)` would also delete the parent Query. It would not
+ delete the parent Database() though, as that is still referenced
+ from the variable *db* in which it is stored.
Pretty much the same is valid for all other objects in the
hierarchy, such as :class:`Query`, :class:`Messages`,