def init(cls, typ, class2type):
        """
        Defines custom fields in the value factory so that the importer can find them
        @param typ
        @param class2type
        """
        field = typ.getField(cls.FIELD_NAME)
        class2type.put( StrStrHashMap , typ )
        typ.setComponentType( StrStrHashMap )
        typ.setImportExportHelper( StrStrHashMapSerializer(typ, field))
        typ.putValidator(field, Validator_object.get(1))
        typ.lock()
def add_backend(self, backend):
        """
        Adds a new backend to the list

        @param backend_id: the id of the backend to add
        """
        if backend:
            backend_iter = self.liststore.append([
                backend.get_id(),
                self.dialog.get_pixbuf_from_icon_name(backend.get_icon(),
                                                      16),
                backend.get_human_name(),
                self._get_markup_for_tags(backend.get_attached_tags()),
            ])
            self.backendid_to_iter[backend.get_id()] = backend_iter