code: func ChaincodePackageExists(ccname string, ccversion string) (bool, error) {
  	path := filepath.Join(chaincodeInstallPath, ccname+"."+ccversion)
  	_, err := os.Stat(path)
  	if err == nil {
  		// chaincodepackage already exists
  		return true, nil
  	}
  	return false, err
  }
docs: // ChaincodePackageExists returns whether the chaincode package exists in the file system