VERIFICATION:- FAILED

Concrete playback
```
#[test]
fn kani_concrete_playback_harness
    let concrete_vals: Vec<Vec<u8>> = vec![
        // -128
        vec![128],
        // -101
        vec![155],
        // 0
        vec![0],
        // 'e'
        vec![101],
        // 127
        vec![127]
    ];
    kani::concrete_playback_run(concrete_vals, harness);
}
```