'TypeError: can only concatenate str (not "NoneType") to str' problem and solution here!

[mykeehu]

When I click on the Generate button, I get this error:
I:\audiocraft_plus\venv\lib\site-packages\gradio\components\textbox.py:163: UserWarning: Using the update method is deprecated. Simply return a new object instead, e.g. return gr.Textbox(...) instead of return gr.Textbox.update(...).
warnings.warn(
Traceback (most recent call last):
File "I:\audiocraft_plus\venv\lib\site-packages\gradio\queueing.py", line 406, in call_prediction
output = await route_utils.call_process_api(
File "I:\audiocraft_plus\venv\lib\site-packages\gradio\route_utils.py", line 226, in call_process_api
output = await app.get_blocks().process_api(
File "I:\audiocraft_plus\venv\lib\site-packages\gradio\blocks.py", line 1554, in process_api
result = await self.call_function(
File "I:\audiocraft_plus\venv\lib\site-packages\gradio\blocks.py", line 1192, in call_function
prediction = await anyio.to_thread.run_sync(
File "I:\audiocraft_plus\venv\lib\site-packages\anyio\to_thread.py", line 33, in run_sync
return await get_asynclib().run_sync_in_worker_thread(
File "I:\audiocraft_plus\venv\lib\site-packages\anyio_backends_asyncio.py", line 877, in run_sync_in_worker_thread
return await future
File "I:\audiocraft_plus\venv\lib\site-packages\anyio_backends_asyncio.py", line 807, in run
result = context.run(func, *args)
File "I:\audiocraft_plus\venv\lib\site-packages\gradio\utils.py", line 659, in wrapper
response = f(*args, **kwargs)
File "I:\audiocraft_plus\app.py", line 826, in predict_full
custom_model = "models/" + custom_model
TypeError: can only concatenate str (not "NoneType") to str

Here is the solution:
use pip install gradio_client==0.6.0 command in your venv, and that's it!