AttributeError: 'NoneType' object has no attribute 'request'

[Automation-Terry]

Traceback (most recent call last):
File "D:\Anaconda3\lib\site-packages\gradio\queueing.py", line 456, in call_prediction
output = await route_utils.call_process_api(
File "D:\Anaconda3\lib\site-packages\gradio\route_utils.py", line 232, in call_process_api
output = await app.get_blocks().process_api(
File "D:\Anaconda3\lib\site-packages\gradio\blocks.py", line 1522, in process_api
result = await self.call_function(
File "D:\Anaconda3\lib\site-packages\gradio\blocks.py", line 1156, in call_function
prediction = await utils.async_iteration(iterator)
File "D:\Anaconda3\lib\site-packages\gradio\utils.py", line 514, in async_iteration
return await iterator.anext()
File "D:\Anaconda3\lib\site-packages\gradio\utils.py", line 507, in anext
return await anyio.to_thread.run_sync(
File "D:\Anaconda3\lib\site-packages\anyio\to_thread.py", line 28, in run_sync
return await get_asynclib().run_sync_in_worker_thread(func, *args, cancellable=cancellable,
File "D:\Anaconda3\lib\site-packages\anyio_backends_asyncio.py", line 818, in run_sync_in_worker_thread
return await future
File "D:\Anaconda3\lib\site-packages\anyio_backends_asyncio.py", line 754, in run
result = context.run(func, *args)
File "D:\Anaconda3\lib\site-packages\gradio\utils.py", line 490, in run_sync_iterator_async
return next(iterator)
File "D:\Anaconda3\lib\site-packages\gradio\utils.py", line 661, in gen_wrapper
yield from f(*args, **kwargs)
File "D:\software\ai_code_reader-master\gr_funcs.py", line 164, in change_code_lang
response = gpt_server.request_llm(sys_prompt, [(user_prompt, None)])
File "D:\software\ai_code_reader-master\gpt_server.py", line 24, in request_llm
return model.request(sys_prompt, user_prompt, stream)
AttributeError: 'NoneType' object has no attribute 'request'