code: func (o *Operation) InterfaceSignature() string {
  	var buf bytes.Buffer
  	err := tplInfSig.Execute(&buf, o)
  	if err != nil {
  		panic(err)
  	}
  
  	return strings.TrimSpace(buf.String())
  }
docs: // InterfaceSignature returns a string representing the Operation's interface{}
  // functional signature.