public void performActionOnElement(IntroduceOperation operation) {
    if (!checkEnabled(operation)) {
      showCanNotIntroduceErrorHint(operation.getProject(), operation.getEditor());
      return;
    }
    final PsiElement element = operation.getElement();
    final PyExpression initializer = getInitializerForElement(element);
    operation.setInitializer(initializer);

    if (initializer != null) {
      operation.setOccurrences(getOccurrences(element, initializer));
      operation.setSuggestedNames(getSuggestedNames(initializer));
    }
    if (operation.getOccurrences().size() == 0) {
      operation.setReplaceAll(false);
    }

    performActionOnElementOccurrences(operation);
  }
public void performActionOnElement(IntroduceOperation operation)