for the "File not found.", would you suggest doing it this way?

```
if not os.path.exists(render_setting_path):
        raise IOError('File not found.')
```

we are already sure they exist unless this fails to work
```
path = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
render_settings_path = os.path.join(path, 'render_settings/', sname)
```