How to use the plac.iterable function in plac

def main(verbose, interactive, multiline, serve, batch, test, fname=None,
         *extra):
    "Runner for plac tools, plac batch files and plac tests"
    baseparser = plac.parser_from(main)
    if fname is None:
        baseparser.print_help()
    elif sys.argv[1] == fname:  # script mode
        plactool = plac.import_main(fname)
        plactool.prog = os.path.basename(sys.argv[0]) + ' ' + fname
        out = plac.call(plactool, sys.argv[2:], eager=False)
        if plac.iterable(out):
            for output in out:
                print(output)
        else:
            print(out)
    elif interactive or multiline or serve:
        plactool = plac.import_main(fname, *extra)
        plactool.prog = ''
        i = plac.Interpreter(plactool)
        if interactive:
            i.interact(verbose=verbose)
        elif multiline:
            i.multiline(verbose=verbose)
        elif serve:
            i.start_server(serve)
    elif batch:
        run((fname,) + extra, 'execute', verbose)