Object pk=primaryKeyObjectForObject(eo); if(pk == null) return null; if(pk instanceof String || pk instanceof Number) { return pk.toString(); } return NSPropertyListSerialization.stringFromPropertyList(pk);
return _stringForPrimaryKey(primaryKeyObjectForObject(eo));
    public static String primaryKeyStringForObject(EOEnterpriseObject eo) {        Object pk=primaryKeyObjectForObject(eo);        if(pk == null)            return null;        if(pk instanceof String || pk instanceof Number) {            return pk.toString();        }        return NSPropertyListSerialization.stringFromPropertyList(pk);    }