在ios上跑pocounit报这个warning，Fail to stop result emitter: "SiteSnapshot"

在ios上跑pocounit报下列warning，有什么办法屏蔽掉吗？

./usr/local/lib/python3.7/site-packages/pocounit/case.py:211: UserWarning: Fail to stop result emitter: "SiteSnapshot". You can report this error to the developers or just ignore it. Error message:
Labconfig.getIsLogJavis():False
"Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/pocounit/case.py", line 207, in run
emitter.stop()
File "/usr/local/lib/python3.7/site-packages/pocounit/result/site_snapshot.py", line 32, in stop
self.snapshot('caseEnd')
File "/usr/local/lib/python3.7/site-packages/pocounit/result/site_snapshot.py", line 38, in snapshot
self.snapshot_screen(site_id)
File "/usr/local/lib/python3.7/site-packages/pocounit/result/site_snapshot.py", line 60, in snapshot_screen
b64img, fmt = self.poco.snapshot()
File "/usr/local/lib/python3.7/site-packages/poco/pocofw.py", line 433, in snapshot
return self.agent.screen.getScreen(width)
File "/usr/local/lib/python3.7/site-packages/poco/utils/airtest/screen.py", line 21, in getScreen
return base64.b64encode(open(savepath, 'rb').read()), 'png'
TypeError: expected str, bytes or os.PathLike object, not NoneType
"
.format(emitter.__class__.__name__, traceback.format_exc()))