* some worlds: some typing in `LocalRom`
### `read_bytes`
It's not safe to return `bytearray` when we think it's `bytes`
```python
a = rom.read_bytes(8, 3)
hash(a) # This won't crash, right?
```
### `write_bytes`
`Iterable[SupportsIndex]` is what's required for `bytearray.__setitem__(slice, values)`
We need to add `__len__` for the `len(values)` in this function.
* remove `object` inheritance
280b67f996