FIx: options are nested on multiple command

Option values are nested when multiple commands exists over than 3 times.

```
bin/hyperloop --optionA=1
==> 1 (OK)

bin/hyperloop --optionA=1 --optionA=2
==> [1, 2] (OK)

bin/hyperloop --optionA=1 --optionA=2 --optionB=3
==> [[1, 2] 3] (NG)
```