Why codex is returning same response for all top_n results?

Prompting
1

I am using Codex API for automated code completion. I am invoking Codex API with the following parameters:

            model="code-davinci-002",
            prompt=input_prompt,
            temperature=0,
            max_tokens=500,
            top_p=1,            
            n=5, # number_of_suggestions
            frequency_penalty=0,
            presence_penalty=0,
            stop=STOP_STR,
        )``` 

But I am always getting the same `response` for all `top_k` results returned by the Codex API. 

What is getting wrong here?