public void performAction(IntroduceOperation operation) {
    final PsiFile file = operation.getFile();
    if (!CommonRefactoringUtil.checkReadOnlyStatus(file)) {
      return;
    }
    final Editor editor = operation.getEditor();
    if (editor.getSettings().isVariableInplaceRenameEnabled()) {
      final TemplateState templateState = (TemplateState)TemplateManagerUtilBase.getTemplateState(operation.getEditor());
      if (templateState != null && !templateState.isFinished()) {
        return;
      }
    }

    PsiElement element1 = null;
    PsiElement element2 = null;
    final SelectionModel selectionModel = editor.getSelectionModel();
    boolean singleElementSelection = false;
    if (selectionModel.hasSelection()) {
      element1 = file.findElementAt(selectionModel.getSelectionStart());
      element2 = file.findElementAt(selectionModel.getSelectionEnd() - 1);
      if (element1 instanceof PsiWhiteSpace) {
        int startOffset = element1.getTextRange().getEndOffset();
        element1 = file.findElementAt(startOffset);
      }
      if (element2 instanceof PsiWhiteSpace) {
        int endOffset = element2.getTextRange().getStartOffset();
        element2 = file.findElementAt(endOffset - 1);
      }
      if (element1 == element2) {
        singleElementSelection = true;
      }
    }
    else {
      if (smartIntroduce(operation)) {
        return;
      }
      final CaretModel caretModel = editor.getCaretModel();
      final Document document = editor.getDocument();
      int lineNumber = document.getLineNumber(caretModel.getOffset());
      if ((lineNumber >= 0) && (lineNumber < document.getLineCount())) {
        element1 = file.findElementAt(document.getLineStartOffset(lineNumber));
        element2 = file.findElementAt(document.getLineEndOffset(lineNumber) - 1);
      }
    }
    final Project project = operation.getProject();
    if (element1 == null || element2 == null) {
      showCannotPerformError(project, editor);
      return;
    }

    element1 = PyRefactoringUtil.getSelectedExpression(project, file, element1, element2);
    if (element1 == null || referencesComprehensionIteratorValue(element1)) {
      showCannotPerformError(project, editor);
      return;
    }

    if (singleElementSelection && element1 instanceof PyStringLiteralExpression literal) {
      // Currently introduce for substrings of a multi-part string literals is not supported
      if (literal.getStringNodes().size() > 1) {
        showCannotPerformError(project, editor);
        return;
      }
      final int offset = element1.getTextOffset();
      final TextRange selectionRange = TextRange.create(selectionModel.getSelectionStart(), selectionModel.getSelectionEnd());
      final TextRange elementRange = element1.getTextRange();
      if (!elementRange.equals(selectionRange) && elementRange.contains(selectionRange)) {
        final TextRange innerRange = literal.getStringValueTextRange();
        final TextRange intersection = selectionRange.shiftRight(-offset).intersection(innerRange);
        final TextRange finalRange = intersection != null ? intersection : selectionRange;
        final String text = literal.getText();
        if (getFormatValueExpression(literal) != null && breaksStringFormatting(text, finalRange) ||
            getNewStyleFormatValueExpression(literal) != null && breaksNewStyleStringFormatting(text, finalRange) ||
            breaksStringEscaping(text, finalRange)) {
          showCannotPerformError(project, editor);
          return;
        }
        element1.putUserData(PyReplaceExpressionUtil.SELECTION_BREAKS_AST_NODE, Pair.create(element1, finalRange));
      }
    }

    if (!checkIntroduceContext(file, editor, element1)) {
      return;
    }
    operation.setElement(element1);
    performActionOnElement(operation);
  }
public void performAction(IntroduceOperation operation)