code: def pull(args):
      
      p = OptionParser(pull.__doc__)
      opts, args = p.parse_args(args)
  
      if len(args) != 3:
          sys.exit(not p.print_help())
  
      prefix = get_prefix()
      version, partID, unitigID = args
      s = ".".join(args)
  
      cmd = "tigStore"
      cmd += " -g ../{0}.gkpStore -t ../{0}.tigStore".format(prefix)
      cmd += " {0} -up {1} -d layout -u {2}".format(version, partID, unitigID)
  
      unitigfile = "unitig" + s
      sh(cmd, outfile=unitigfile)
  
      return unitigfile
docs: %prog pull version partID unitigID
  
      For example, `%prog pull 5 530` will pull the utg530 from partition 5
      The layout is written to `unitig530`