def METHOD_NAME():
    """
    Main utility function for OSG topology CLI.
    """
    oparser = get_parser()
    args = oparser.parse_args()
    if not args.which:
        oparser.error(f"No command specified; see {sys.argv[0]} --help for usage")
    if getattr(args, "filter", None) is not None:
        if args.fqdn:
            args.fqdn_filter = args.filter.strip()
        else:
            args.name_filter = args.filter.strip()
    try:
        with open(args.email_file, 'r') as f:
            contents = f.read()
            args.contact_emails = contents.split('\n')
    except (AttributeError, TypeError):
        pass  # --email-from-file not specified
    except IOError as exc:
        sys.exit("Failed to read email file: %s" % exc)
    except UnicodeDecodeError as exc:
        sys.exit("Invalid unicode in email file: %s" % exc)
    commands = {"list-resource-contacts": list_resource_contacts,
                "list-vo-contacts": list_vo_contacts,
                "list-contacts": list_contacts,
               }
    command = commands[args.which]
    return command(args)