@Nullable
  public PsiElement addDeclaration(IntroduceOperation operation, PsiElement declaration) {
    final PsiElement expression = operation.getInitializer();
    final Pair<PsiElement, TextRange> data = expression.getUserData(PyReplaceExpressionUtil.SELECTION_BREAKS_AST_NODE);
    if (data == null) {
      return addDeclaration(expression, declaration, operation);
    }
    else {
      return addDeclaration(data.first, declaration, operation);
    }
  }
@Nullable
  public PsiElement addDeclaration(IntroduceOperation operation, PsiElement declaration)