[Dúvida] Código passado pelo professor não funciona

O código passado pelo professor nessa aula não funciona. Já configurei o ambiente como indicado, tento rodar o código e aparece o seguinte erro, que não consegui identificar do que se trata. O VS Code aponta um problema na linha de código
modelo = ChatOpenAI(
model="gpt-3.5-turbo",
temperature=0.5,
api_key=api_key ERRO
)

Abaixo, segue mensagem de erro:

Traceback (most recent call last):
File "d:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\main2.py", line 20, in
resposta = modelo.invoke(prompt)
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\langchain_core\language_models\chat_models.py", line 471, in invoke
self.generate_prompt(
~~~~~~~~~~~~~~~~~~~~^
[self._convert_input(input)],
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...<6 lines>...
**kwargs,
^^^^^^^^^
).generations[0][0],
^
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\langchain_core\language_models\chat_models.py", line 1749, in generate_prompt
return self.generate(prompt_messages, stop=stop, callbacks=callbacks, **kwargs)
~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\langchain_core\language_models\chat_models.py", line 1556, in generate
self._generate_with_cache(
~~~~~~~~~~~~~~~~~~~~~~~~~^
m,
^^
...<2 lines>...
**kwargs,
^^^^^^^^^
)
^
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\langchain_core\language_models\chat_models.py", line 1896, in _generate_with_cache
result = self._generate(
messages, stop=stop, run_manager=run_manager, **kwargs
)
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\langchain_openai\chat_models\base.py", line 1655, in _generate
_handle_openai_api_error(e)
~~~~~~~~~~~~~~~~~~~~~~~~^^^
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\langchain_openai\chat_models\base.py", line 1650, in _generate
raw_response = self.client.with_raw_response.create(**payload)
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\openai_legacy_response.py", line 367, in wrapped
return cast(LegacyAPIResponse[R], func(*args, **kwargs))
~~~~^^^^^^^^^^^^^^^^^
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\openai_utils_utils.py", line 287, in wrapper
return func(*args, **kwargs)
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\openai\resources\chat\completions\completions.py", line 1211, in create
return self._post(
~~~~~~~~~~^
"/chat/completions",
^^^^^^^^^^^^^^^^^^^^
...<47 lines>...
stream_cls=Stream[ChatCompletionChunk],
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\openai_base_client.py", line 1314, in post
return cast(ResponseT, self.request(cast_to, opts, stream=stream, stream_cls=stream_cls))
~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "D:\Documentos\VS Code\Projects\4741-LangChain-e-Python-criando-ferramentas-com-a-LLM-OpenAI-main\langchain\Lib\site-packages\openai_base_client.py", line 1087, in request
raise self._make_status_error_from_response(err.response) from None
openai.RateLimitError: Error code: 429 - {'error': {'message': 'You exceeded your current quota, please check your plan and billing details. For more information on this error, read the docs: https://platform.openai.com/docs/guides/error-codes/api-errors.', 'type': 'insufficient_quota', 'param': None, 'code': 'insufficient_quota'}}