Python-OpenCv加载级联分类器,cv2.error: OpenCV(3.4.11) C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-
cv2.error:OpenCV(3.4.11)C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-2lgn4oq5\opencv\modules\objdetect\src\cascadedetect.cpp:1729:error:(-215:Assertionfailed)!empty()infunction'cv::CascadeClas