Tweak docs - make `is_ring` description more precise
@@ -1008,7 +1008,7 @@ A ring with an undesired orientation can be reversed like this:
.. attribute:: object.is_ring
- Returns ``True`` if the feature is closed. A closed feature's `boundary`
+ Returns ``True`` if the feature is a closed and simple ``LineString``. A closed feature's `boundary`
coincides with the empty set.
.. code-block:: pycon
