Help when specifying multiple WARC files to indexer is confusing

[machawk1]

ipwb index --help returns:

usage: ipwb [-h] [-e] [-c] [--compressFirst] [--debug]
            index <warcPath> [index <warcPath> ...]

This is likely attributed to the indexer's argument parser. Changing the culprit line:

indexParser.add_argument(
       'warcPath',
       help="Path to a WARC[.gz] file",
       metavar="index <warcPath>",
       nargs='+',
       default=None)

to:

indexParser.add_argument(
       'warcPath',
       help="Path to a WARC[.gz] file",
       metavar="index <warcPath>",
       nargs='3',
       default=None)

produces:

usage: ipwb [-h] [-e] [-c] [--compressFirst] [--debug]
            index <warcPath> index <warcPath> index <warcPath>

From the first snippet above, we want to accept multiple WARCs but not convey that index is required before each one. Changing nargs to 1 prevents correct parsing of multiple WARC files as specified when invoked.