update changelog, indicate return value for get_graph in `remove_tr…

…ansitions`

Changelog.md

@@ -11,6 +11,7 @@
 - PR #633: Remove surrounding whitespace from docstrings (thanks @artofhuman)
 - PR #665: Add `on_final` to `Machine` and `NestedState` constructor and `final` to `State`. Callbacks passed to `on_final` will be executed when a State with `final=True` is entered or all children of a parallel state are final.
 - Bug #626: Process exceptions with `Machine.on_exception` in may_<trigger> as well (thanks @match1)
+- PR #666: Improved handling of removing transitions for `GraphMachine` and `HiearachicalMachine` (thanks @drpjm)
 - Typing:
   + Made state, event and machine property mandatory in (Nested)EventData
   + Transition.dest may be None

transitions/extensions/diagrams.py

@@ -260,8 +260,9 @@ def add_transition(self, trigger, source, dest, conditions=None, unless=None, be
 
     def remove_transition(self, trigger, source="*", dest="*"):
         super(GraphMachine, self).remove_transition(trigger, source, dest)
+        # update all model graphs since some transitions might be gone
         for model in self.models:
-            model.get_graph(force_new=True)
+            _ = model.get_graph(force_new=True)
 
 
 class NestedGraphTransition(TransitionGraphSupport, NestedTransition):