def _create_docker_command(*args, **kwargs):
    """
    Returns a string with the ordered arguments args in order,
    followed by the keyword arguments kwargs (in sorted order, for
    consistency), separated by spaces.

    For example,
    ``_create_docker_command('./myprogram', 5, 6, wibble=7, wobble=8)``
    returns ``"./myprogram 5 6 --wibble 7 --wobble 8"``.
    """
    return " ".join([str(x) for x in args] +
                    ["--{} {}".format(k, v)
                     for k, v in sorted(kwargs.items())])