'Log to file. ("-" for stdout, "+" for stderr; default: "-")'

def opt_log_file(self, fileName):

    if (fileName == '-'):
        self['logFile'] = stdout
        return
    if (fileName == '+'):
        self['logFile'] = stderr
        return
    try:
        self['logFile'] = openFile(fileName, 'a')
    except EnvironmentError as e:
        exit(ExitStatus.EX_IOERR, 'Unable    to    open    log    file    {!r}:    {}'.format(fileName, e))
