diff --git a/odoo-rpc.py b/odoo-rpc.py
index 9a8e898..f97a8e9 100644
--- a/odoo-rpc.py
+++ b/odoo-rpc.py
@@ -229,7 +229,7 @@ def lookup( model, domains ):
 		data = inst.read()[0]
 		size = len( json.dumps(data, indent=4) )
 		filename = json_path( model, inst.id )
-		if filename in stack:
+		if filename in [item.file for item in stack]:
 			continue
 
 		# print( 'Preparing data for %s' % (filename) )