diff --git a/oauth2client/django_orm.py b/oauth2client/django_orm.py
index 2f32faa..c818ea2 100644
--- a/oauth2client/django_orm.py
+++ b/oauth2client/django_orm.py
@@ -31,7 +31,7 @@
 
   __metaclass__ = models.SubfieldBase
 
-  def db_type(self):
+  def db_type(self, connection=None):
     return 'VARCHAR'
 
   def to_python(self, value):
@@ -49,7 +49,7 @@
 
   __metaclass__ = models.SubfieldBase
 
-  def db_type(self):
+  def db_type(self, connection=None):
     return 'VARCHAR'
 
   def to_python(self, value):