code: func (es MultiError) Error() string {
  	var buf bytes.Buffer
  
  	if len(es) > 1 {
  		fmt.Fprintf(&buf, "%d errors: ", len(es))
  	}
  
  	for i, err := range es {
  		if i != 0 {
  			buf.WriteString("; ")
  		}
  		buf.WriteString(err.Error())
  	}
  
  	return buf.String()
  }
docs: // Returns a concatenated string of the contained errors