code: func NewPremailerFromString(doc string, options *Options) (Premailer, error) {
  	read := strings.NewReader(doc)
  	d, err := goquery.NewDocumentFromReader(read)
  	if err != nil {
  		return nil, err
  	}
  	return NewPremailer(d, options), nil
  }
docs: // NewPremailerFromString take in a document in string format
  // and create a goquery.Document
  // and then create and Premailer instance.