fix: add get_value() convenience function

tests/test_app.py

@@ -48,6 +48,32 @@ class TestAppHandler(FileTestCase):
     def test_get_enum(self):
         self.assertIs(self.app.get_enum(), wuttjamaican.enum)
 
+    def test_get_value(self):
+
+        class Object:
+            def __init__(self, **kw):
+                self.__dict__.update(kw)
+
+        class Dict(dict):
+            pass
+
+        # dict object
+        obj = {"foo": "bar"}
+        self.assertEqual(self.app.get_value(obj, "foo"), "bar")
+
+        # object w/ attrs
+        obj = Object(foo="bar")
+        self.assertEqual(self.app.get_value(obj, "foo"), "bar")
+
+        # dict-like w/ attrs
+        obj = Dict({"foo": "bar"})
+        obj.baz = "yyy"
+        self.assertEqual(self.app.get_value(obj, "baz"), "yyy")
+
+        # missing attr
+        obj = Object(foo="bar")
+        self.assertRaises(AttributeError, self.app.get_value, obj, "baz")
+
     def test_load_object(self):
 
         # just confirm the method works on a basic level; the