From 88d6cc952737536533efa03ef02f55da688c8a27 Mon Sep 17 00:00:00 2001
From: Konsta Vesterinen <konsta.vesterinen@gmail.com>
Date: Tue, 21 Jan 2014 14:40:04 +0200
Subject: [PATCH] Fix issues with inheritance

---
 sqlalchemy_utils/aggregates.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sqlalchemy_utils/aggregates.py b/sqlalchemy_utils/aggregates.py
index 6f4af3d..e12f3d7 100644
--- a/sqlalchemy_utils/aggregates.py
+++ b/sqlalchemy_utils/aggregates.py
@@ -281,7 +281,7 @@ class AggregatedAttribute(declared_attr):
         self.relationship = relationship
 
     def __get__(desc, self, cls):
-        if not hasattr(cls, '__aggregates__'):
+        if '__aggregates__' not in cls.__dict__:
             cls.__aggregates__ = {}
         cls.__aggregates__[desc.fget.__name__] = {
             'expression': desc.fget,
@@ -413,7 +413,7 @@ class AggregationManager(object):
         )
 
     def update_generator_registry(self, mapper, class_):
-        if hasattr(class_, '__aggregates__'):
+        if '__aggregates__' in class_.__dict__:
             for key, value in six.iteritems(class_.__aggregates__):
                 relationships = []
                 rel_class = class_