code: def index(args):
      
      p = OptionParser(index.__doc__)
      opts, args = p.parse_args(args)
  
      if len(args) != 1:
          sys.exit(not p.print_help())
  
      dbfile, = args
      check_index(dbfile)
docs: %prog index database.fasta
  
      Wrapper for `bwa index`. Same interface.