Cleanup extending docs example

vidartf · vidartf · commit 186ab93df927 · 2018-05-16T13:40:44.000+02:00
diff --git a/docs/source/extending.rst b/docs/source/extending.rst
@@ -44,6 +44,7 @@ Python::
     import pythreejs
 
     class CubicLattice(pythreejs.Blackbox):
+        _model_name: traitlets.Unicode('CubicLatticeModel').tag(sync=True)
         _model_module = traitlets.Unicode('my_module_name').tag(sync=True)
 
         basis = traitlets.List(
