Check if a provided path exists and is readonly.

    Permissions check is `bool(path.stat & stat.S_IREAD)` or `not os.access(path, os.W_OK)`

def is_readonly_path(fn):
    """Check if a provided path exists and is readonly.

    Permissions check is `bool(path.stat & stat.S_IREAD)` or `not os.access(path, os.W_OK)`
    """

    fn = fs_encode(fn)
    if os.path.exists(fn):
        file_stat = os.stat(fn).st_mode
        return not bool(file_stat & stat.S_IWRITE) or not os.access(fn, os.W_OK)
    return False