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 range(cls, dataset, dimension):
        dimension = dataset.get_dimension(dimension, strict=True)
        column = dataset.data[dimension.name]
        if dimension.nodata is not None:
            column = cls.replace_value(column, dimension.nodata)
        if column.dtype.kind == 'O':
            return np.NaN, np.NaN
        else:
            return finite_range(column, column.min(), column.max())