Update test_hangup.py

Author: brianluisgomez

test/unit/bxml/test_hangup.py

@@ -24,5 +24,5 @@ def test_to_bxml(self):
 
     def test_add_verb(self):
         with pytest.raises(AttributeError):
-            self.tag.add_verb(self.test_verb)
+            self.hangup.add_verb(self.test_verb)