def METHOD_NAME(target="/sys"):
    flags = [2 | 4 | 8]  # MS_NOSUID | MS_NODEV | MS_NOEXEC
    flags.append(1 << 18)  # MS_PRIVATE
    flags.append(1 << 19)  # MS_SLAVE
    for fl in flags:
        ret = libc.mount(b"none", target.encode("ascii"), b"sysfs", fl, None)
        if ret == -1:
            e = ctypes.get_errno()
            raise OSError(e, os.strerror(e))