code: func (a *Webhook) ValidateInitialization() error {
  	if a.hookSource == nil {
  		return fmt.Errorf("kubernetes client is not properly setup")
  	}
  	if err := a.namespaceMatcher.Validate(); err != nil {
  		return fmt.Errorf("namespaceMatcher is not properly setup: %v", err)
  	}
  	if err := a.clientManager.Validate(); err != nil {
  		return fmt.Errorf("clientManager is not properly setup: %v", err)
  	}
  	return nil
  }
docs: // ValidateInitialization implements the InitializationValidator interface.