def _add_folder_positional_arg(arg_parser):
    """
    Adds folders and/or filenames parameter to a parser.
    :param arg_parser: ArgumentParser parser to add this argument to.
    """
    arg_parser.add_argument('folder', metavar='Folder', help=
        "Name of the folder to download the project contents into. If not specified it will use the name of the project with spaces translated to '_'. "
        , nargs='?')
