public DataTable subTable(int fromRow, int fromColumn) {
        return subTable(fromRow, fromColumn, height(), width());
    }
@Test
    void subTable_throws_for_invalid_from_to_column() {
        DataTable table = createSimpleTable();
        assertThrows(IllegalArgumentException.class, () -> table.subTable(0, 2, 1, 1));
    }