OpenCV(4.5.1) C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-r2ue8w6k\opencv\modules\imgproc\src\resize.cpp:4051: error: (-215:Assertion failed) !ssize.empty() in function 'cv::resize' code example

Example: cv2.imshow("frame",frame) cv2.error: OpenCV(4.4.0) C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-wwma2wne\opencv\modules\highgui\src\window.cpp:376: error: (-215:Assertion failed) size.width>0

cv2.imshow("frame",frame) cv2.error: OpenCV(4.4.0) C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-wwma2wne\opencv\modules\highgui\src\window.cpp:376: error: (-215:Assertion failed) size.width>0