I am using the code below to build a simple Assistant that is capable of reading a pdf file attached as a part of a message thread. But this does not seem to work as even though the message_files object is being created it does not seem to get uploaded and I am unsure as for the cause of this since this is the code from the api documentation.

client = OpenAI()
assist_id='some id'
# Upload the user provided file to OpenAI
message_file = client.files.create(
  file=open("./file.pdf", "rb"), purpose="assistants"
)

# Create a thread and attach the file to the message
thread = client.beta.threads.create(
  messages=[
    {
      "role": "user",
      "content": "What is the highest value in the file?",
      # Attach the new file to the message.
      "attachments": [
        { "file_id": message_file.id, "tools": [{"type": "file_search"}] }
      ],
    }
  ]
)
print(thread.tool_resources.file_search)
assistant_id=assist_id
thread_id= thread.id
run=client.beta.threads.runs.create(
    thread_id=thread_id,
    assistant_id=assistant_id,
    instructions="Ensure to provide a simple response for the average person to be able to understand"
)
def wait_for_run(client,thread_id,run_id,sleep_interval=5):
    while True:
        try:
            run=client.beta.threads.runs.retrieve(thread_id=thread_id,run_id=run_id)
            if run.completed_at:
                print(f"Run completed")
                logging.info(f"Run completed")
                message=client.beta.threads.messages.list(thread_id=thread_id)
                last_message=message.data[0]
                response=last_message.content[0].text.value
                print(f"Assistants Response:{response}")
                break
        except Exception as e:
            logging.error(f"AN error occured while retrieving the run:{e}")
            break
        logging.info("Waiting for run to complete....")
        time.sleep(sleep_interval)
        
wait_for_run(client=client,thread_id=thread_id,run_id=run.id)

For more context I tried other methods like building vector stores but I only found examples where it was being uploaded to the assistant as a knowledge base I do not want that as the information being sent in a thread must be available only there and outside of the same thread should not be available.
I understand that there is some type of bug going around relating to this but I wish to get this operational so any and all help regarding this issue is much appreciated.