improve perf

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@15049 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5SyncML/Subscription.py

@@ -1240,7 +1240,7 @@ class Subscription(Folder, SyncCode):
     """
       add a Signature to the subscription
     """
-    if signature.getGid() in self.getGidList():
+    if self.getSignatureFromGid(signature.getGid()) != None:
       self.delSignature(signature.getGid())
     self._setObject(signature.getGid(), aq_base(signature))