L6_Agent Observation empty but qa got right answer

i have encounter a question:

where: the L6_Agent, in section sort people by last name

  1. the python_repl output “”
  2. the second time call openai API, there is no Observation

despite all 2 differences, the qa got right answer!
is that sound?

[tool/start] [1:chain:AgentExecutor > 4:tool:Python_REPL] Entering Tool run with input:
"sorted([['Harrison', 'Chase'], ['Lang', 'Chain'], ['Dolly', 'Too'], ['Elle', 'Elem'], ['Geoff', 'Fusion'], ['Trance', 'Former'], ['Jen', 'Ayai']], key=lambda x: (x[1], x[0]))"
[tool/end] [1:chain:AgentExecutor > 4:tool:Python_REPL] [1ms] Exiting Tool run with output:

[llm/start] [1:chain:AgentExecutor > 5:chain:LLMChain > 6:llm:ChatOpenAI] Entering LLM run with input:
  "prompts": [
    "Human: You are an agent designed to write and execute python code to answer questions.
    You have access to a python REPL, which you can use to execute python code.
    If you get an error, debug your code and try again.
    Only use the output of your code to answer the question. 
    You might know the answer without running any code, but you should still run the code to get the answer.
    If it does not seem like you can write code to answer the question, just return \"I don't know\" as the answer.
    Python_REPL: A Python shell. Use this to execute python commands. Input should be a valid python command. If you want to see the output of a value, you should print it out with `print(...)`.
    Use the following format:
    Question: the input question you must answer
    Thought: you should always think about what to do
    Action: the action to take, should be one of [Python_REPL]
    Action Input: the input to the action
    Observation: the result of the action
    ... (this Thought/Action/Action Input/Observation can repeat N times)
    Thought: I now know the final answer
    Final Answer: the final answer to the original input question
    Question: Sort these customers by last name and then first name and print the output: [['Harrison', 'Chase'], ['Lang', 'Chain'], ['Dolly', 'Too'], ['Elle', 'Elem'], ['Geoff', 'Fusion'], ['Trance', 'Former'], ['Jen', 'Ayai']]
    Thought:I can use the `sorted()` function to sort the list of customers. I will need to provide a key function that specifies the sorting order based on last name and then first name.
    Action: Python_REPL
    Action Input: sorted([['Harrison', 'Chase'], ['Lang', 'Chain'], ['Dolly', 'Too'], ['Elle', 'Elem'], ['Geoff', 'Fusion'], ['Trance', 'Former'], ['Jen', 'Ayai']], key=lambda x: (x[1], x[0]))