1 files changed, 18 insertions, 0 deletions
diff --git a/lib/sqlalchemy/util.py b/lib/sqlalchemy/util.py
index 08b281684..d4627974b 100644
--- a/lib/sqlalchemy/util.py
+++ b/lib/sqlalchemy/util.py
@@ -127,6 +127,24 @@ class SimpleProperty(object):
         else:
             return getattr(obj, self.key)
 
+class NotImplProperty(object):
+  """a property that raises ``NotImplementedError``."""
+  
+  def __init__(self, doc):
+      self.__doc__ = doc
+      
+  def __set__(self, obj, value):
+      raise NotImplementedError()
+
+  def __delete__(self, obj):
+      raise NotImplementedError()
+
+  def __get__(self, obj, owner):
+      if obj is None:
+          return self
+      else:
+          raise NotImplementedError()
+  
 class OrderedProperties(object):
     """An object that maintains the order in which attributes are set upon it.