Retrieves command line arguments.

    :return: Namespace.
    :rtype: Namespace

def get_command_line_arguments():
    """
    Retrieves command line arguments.

    :return: Namespace.
    :rtype: Namespace
    """

    parser = argparse.ArgumentParser(add_help=False)

    parser.add_argument("-h",
                        "--help",
                        action="help",
                        help="'Displays this help message and exit.'")

    parser.add_argument("-t",
                        "--title",
                        type=unicode,
                        dest="title",
                        help="'Package title.'")

    parser.add_argument("-i",
                        "--input",
                        type=unicode,
                        dest="input",
                        help="'Input file to convert.'")

    parser.add_argument("-o",
                        "--output",
                        type=unicode,
                        dest="output",
                        help="'Output file.'")

    parser.add_argument("-c",
                        "--content_directory",
                        type=unicode,
                        dest="content_directory",
                        help="'Content directory.'")

    if len(sys.argv) == 1:
        parser.print_help()
        sys.exit(1)

    return parser.parse_args()