code: func cW(w io.Writer, useColor bool, color []byte, s string, args ...interface{}) {
  	if isTTY && useColor {
  		w.Write(color)
  	}
  	fmt.Fprintf(w, s, args...)
  	if isTTY && useColor {
  		w.Write(reset)
  	}
  }
docs: // colorWrite