def subparser(subparsers):
    """Define the `kevlar split` command-line interface."""
    desc = 'Split partitioned reads into N output files.'
    subparser = subparsers.add_parser('split', description=desc)
    subparser.add_argument('infile', help=
        'input file; partitioned reads in augmented Fastq/Fasta format')
    subparser.add_argument('numfiles', type=int, help=
        'number of output files to create')
    subparser.add_argument('base', help='prefix of all output files')
