def _validate_args(env, args):
    """Raises an ArgumentError if the given arguments are not valid."""

    if all([args['cpu'], args['flavor']]):
        raise exceptions.ArgumentError(
            '[-c | --cpu] not allowed with [-f | --flavor]')

    if all([args['memory'], args['flavor']]):
        raise exceptions.ArgumentError(
            '[-m | --memory] not allowed with [-f | --flavor]')

    if all([args['dedicated'], args['flavor']]):
        raise exceptions.ArgumentError(
            '[-d | --dedicated] not allowed with [-f | --flavor]')

    if all([args['host_id'], args['flavor']]):
        raise exceptions.ArgumentError(
            '[-h | --host-id] not allowed with [-f | --flavor]')

    if all([args['userdata'], args['userfile']]):
        raise exceptions.ArgumentError(
            '[-u | --userdata] not allowed with [-F | --userfile]')

    image_args = [args['os'], args['image']]
    if all(image_args):
        raise exceptions.ArgumentError(
            '[-o | --os] not allowed with [--image]')

    while not any([args['os'], args['image']]):
        args['os'] = env.input("Operating System Code", default="", show_default=False)
        if not args['os']:
            args['image'] = env.input("Image", default="", show_default=False)
Raises an ArgumentError if the given arguments are not valid.