never give empty list as default parameter of methods

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@19650 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Tool/RuleTool.py

@@ -122,7 +122,7 @@ class RuleTool (UniqueObject, Folder):
 
     security.declareProtected(Permissions.AccessContentsInformation,
         'searchRuleList')
-    def searchRuleList(self, movement, tested_base_category_list=[], **kw):
+    def searchRuleList(self, movement, tested_base_category_list=None, **kw):
       """
       this method searches for rules, as predicates against movement
 
@@ -132,6 +132,9 @@ class RuleTool (UniqueObject, Folder):
       """
       domain_tool = getToolByName(self, "portal_domains")
 
+      if tested_base_category_list is None:
+        tested_base_category_list = []
+
       rule_list = domain_tool.searchPredicateList(context=movement,
           tested_base_category_list=tested_base_category_list,
           portal_type=self.getPortalRuleTypeList(),