编写函数
   
    get_parser
   
   这样地:
  
  def get_parser():
    parser = argparse.ArgumentParser(prog = 'contig2genbank.py', usage= '\n\t%(prog)s [contig ID/ or list of contigs] [output prefix]' , description = "Split a .gbk (.gbff) file and retrieve the information of the contig of interest.",formatter_class=RawTextHelpFormatter)
    parser.add_argument('-s', required = False, type = str, help='Name of input file (mandatory with -g)', metavar='') # used to extract single contigs
    parser.add_argument('-l', required = False, type = str, help='Name of input file  when in list (mandatory)', metavar='') # when giving a list of genomes and contigs to be extracted; see above the list example
    parser.add_argument('-g', required = False, type = str, help='Name of genome file (mandatory with -i)', metavar='') # when using a single genome, -g is the name of genome file in .gbk (.gbff) format
    return parser
  
   
    main
   
   功能如下:
  
  def main():
    parser = get_parser()
    args = parser.parse_args()  # check arguments
    if args.s and args.g:
        with open(args.g, "rU") as genome: #open(args.c + '.gbk','w') as outgbk:
            for record in SeqIO.parse(genome, "genbank"):
                if args.s == record.id:
                    #with open(args.c + '.gbk','w') as outgbk:
                    SeqIO.write([record], open(record.id + ".gbk", "w"), "genbank")
        print record.id + ".gbk created."
    else:
        parser.print_help()