diff --git a/mediagoblin/db/sql/base.py b/mediagoblin/db/sql/base.py
index e10e7739..ca0c8166 100644
--- a/mediagoblin/db/sql/base.py
+++ b/mediagoblin/db/sql/base.py
@@ -51,12 +51,18 @@ class GMGTableBase(object):
     query = Session.query_property()
 
     @classmethod
-    def find(cls, query_dict={}):
+    def find(cls, query_dict=None):
+        if query_dict is None:
+            query_dict = {}
+
         _fix_query_dict(query_dict)
         return cls.query.filter_by(**query_dict)
 
     @classmethod
-    def find_one(cls, query_dict={}):
+    def find_one(cls, query_dict=None):
+        if query_dict is None:
+            query_dict = {}
+
         _fix_query_dict(query_dict)
         return cls.query.filter_by(**query_dict).first()