fix typo in previous commit

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@16772 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Form/Form.py

@@ -771,7 +771,7 @@ class ERP5Form(ZMIForm, ZopePageTemplate):
             for key, value in _dict.items():
                 if value=='':
                     continue
-                if isinstance((value, Method):
+                if isinstance(value, Method):
                     value = Method(value.method_name)
                 elif isinstance(value, TALESMethod):
                     value = TALESMethod(value._text)