code: func NewLogFormatter(out io.Writer) log.Formatter {
  	var ret = logFormatter{}
  	if f, ok := out.(*os.File); ok {
  		ret.colorise = terminal.IsTerminal(int(f.Fd()))
  		ret.escapes = terminal.NewTerminal(f, "").Escape
  	}
  	return &ret
  }
docs: // NewLogFormatter creates a new log.Formatter customised for writer