code: func New(optionals ...int) Progress {
  	if len(optionals) > 0 {
  		if optionals[0] < 0 {
  			panic(ErrBadSize)
  		}
  		return Progress{pre: "Progress", state: "|", sOutput: optionals[0]}
  	}
  	return Progress{pre: "Progress", state: "|"}
  }
docs: // New Progress structure