def AddArguments(cls, argument_group):
    """Adds command line arguments to an argument group.

    This function takes an argument parser or an argument group object and adds
    to it all the command line arguments this helper supports.

    Args:
      argument_group (argparse._ArgumentGroup|argparse.ArgumentParser):
          argparse group.
    """
    storage_formats = sorted(definitions.STORAGE_FORMATS)

    argument_group.add_argument(
        '--storage_format', '--storage-format', action='store',
        choices=storage_formats, dest='storage_format', type=str,
        metavar='FORMAT', default=definitions.DEFAULT_STORAGE_FORMAT, help=(
            'Format of the storage file, the default is: {0:s}. Supported '
            'options: {1:s}'.format(
                definitions.DEFAULT_STORAGE_FORMAT,
                ', '.join(storage_formats))))