code: def test_add_does_not_affect_result_cell(self):
      row = LLMFnOutputRow(data={"result": "hello"}, result_type=str)
      self.assertEqual("hello", row.result_value())
      row.add("column_one", 42)
      row.add("column_two", "forty-two")
      self.assertEqual("hello", row.result_value())
      self.assertEqual(
          {
              "column_one": 42,
              "column_two": "forty-two",
              "result": "hello",
          },
          dict(row),
      )
      self.assertEqual("result", row.result_key())
      self.assertEqual("hello", row.result_value())
  
file_path: generative-ai-python/tests/notebook/lib/test_llmfn_output_row.py
imports: from __future__ import annotations
  from typing import Any, Mapping
  from absl.testing import absltest
  from google.generativeai.notebook.lib import llmfn_output_row
label_desc: Use image node_id 8 for calling the LLMFnOutputRowTest obj's underlying member method code with example usage: obj.test_add_does_not_affect_result_cell() without return types