def METHOD_NAME(parser):
    """Capitalize the first character of all words in the title of each action
    group of the passed parser.
    This is useful for consistency when using the sphinx argparse extension,
    which title-cases default action groups only.
    """
    for (
        action_group
    ) in parser._action_groups:  # pylint: disable=protected-access
        action_group.title = action_group.title.title()