fn main() {
    {
        let my_data = vec![
            vec![vec!["1", "2"], vec!["a", "b"]],
        ];
        let _ = my_data;
    }
    let my_data;
    my_data = vec![
        vec![vec!["1", "2"], vec!["a", "b"]],
    ];
    let _ = my_data;
}
