def bedcolumns_parser(subparsers):
    """
    Parser for the bedcolumns tool.
    """
    parser = subparsers.add_parser('bedcolumns', help=
        'determine the numbers of BED and extra columns', description=
        'Determine the number of BED columns and the number of extra columns in a BED file'
        )
    parser.add_argument('bed_file', help='a BED file')
