Implemented a annotations adapter

otto/app.py

@@ -25,6 +25,29 @@ def __call__(self, obj, *args, **kwargs):
         for handler in self.lookup(obj):
             handler(obj, *args, **kwargs)
 
+class Annotation(object):
+    """ Annotation on objects. Annotations are stored in a "_annotations" attribute.
+
+        >>> class MyObj(object):
+        ...     pass
+        >>> o = MyObj()
+        >>> annotations = Annotations(o, 'mynamespace')
+        >>> annotations
+        {}
+    """
+    def __new__(self, obj, namespace):
+        try:
+            annotations = obj._annotations
+        except AttributeError:
+            # XXX Should we check if the object supports __setitem__?
+            obj._annotations = dict()
+            annotations = obj._annotations
+        try:
+            return annotations[namespace]
+        except KeyError:
+            annotations[namespace] = dict()
+            return annotations[namespace]
+
 
 class Application(object):
     """WSGI-application.