1. The line is too long (more than 80 lines) and it is still ugly to break this too long lines with \"\n".
2. The meaning of that line differs. If FILE_UPLOAD_PERMISSIONS and STATIC_FILE_PERMISSIONS both are empty (None), then we are in trouble.
```os.chmod(full_path, None) -> error.```

What about this:
 ```       
        if self.permissions_mode is not None:
            mode = self.permissions_mode
        else:
            mode = settings.FILE_UPLOAD_PERMISSIONS
        if mode:
            os.chmod(full_path, mode)
```