fix NoneType bug for ws_client.py microphone mode

zhaomingwork

2023-05-13 3dcaa9df2f056fefd87736f1cd1cd32679018ba9

 egs/aishell/transformer/utils/prepare_checkpoint.py

@@ -1,8 +1,6 @@
import os
import shutil

from modelscope.pipelines import pipeline
from modelscope.utils.constant import Tasks
from modelscope.hub.snapshot_download import snapshot_download