use boolean constants to make API easier to understand

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@24844 20353a03-c40f-0410-a6d1-a30d3c3de9de

bt5/erp5_base/SkinTemplateItem/portal_skins/erp5_base/Person_getAge.xml

@@ -89,7 +89,7 @@ return Base_translateString("${year} years old", mapping=interval_dict)\n
         </item>
         <item>
             <key> <string>_params</string> </key>
-            <value> <string>at_date=None, year=0</string> </value>
+            <value> <string>at_date=None, year=False</string> </value>
         </item>
         <item>
             <key> <string>errors</string> </key>

bt5/erp5_base/bt/revision

-490
+491
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