1 files changed, 23 insertions, 1 deletions
diff --git a/tutorius/properties.py b/tutorius/properties.py
index f273569..07b1645 100644
--- a/tutorius/properties.py
+++ b/tutorius/properties.py
@@ -138,7 +138,29 @@ class TPropContainer(object):
         """
         Return a deep copy of the dictionary of properties from that object.
         """
-        return deepcopy(self._props) 
+        return deepcopy(self._props)
+
+    def __hash__(self):
+        """
+        Deprecated.
+        
+        Property containers should not be used as keys inside dictionary for
+        the time being. Since containers are mutable, we should definitely
+        use the addressing mechanism to refer to the containers.
+        """
+        # Many places we use containers as keys to store additional data.
+        # Since containers are mutable, there is a need for a hash function
+        # where the result is constant, so we can still lookup old instances.
+        return self.__id
+
+    # Adding methods for pickling and unpickling an object with
+    # properties
+    def __getstate__(self):
+        return dict(id=self.__id, props=self._props.copy())
+
+    def __setstate__(self, dict):
+        self.__id = dict['id']
+        self._props.update(dict['props'])
 
     def __eq__(self, e2):
         return (isinstance(e2, type(self)) and self._props == e2._props)