code: func validateExtendedResourceName(name v1.ResourceName) []error {
  	var validationErrors []error
  	for _, msg := range validation.IsQualifiedName(string(name)) {
  		validationErrors = append(validationErrors, errors.New(msg))
  	}
  	if len(validationErrors) != 0 {
  		return validationErrors
  	}
  	if !v1helper.IsExtendedResourceName(name) {
  		validationErrors = append(validationErrors, fmt.Errorf("%s is an invalid extended resource name", name))
  	}
  	return validationErrors
  }
docs: // validateExtendedResourceName checks whether the specified name is a valid
  // extended resource name.