error: (-215:assertion failed) !_src.empty() in function 'cv::cvtcolor'
By Zworis at Mar 08 2020
cv2.error: opencv(4.2.0) c:\projects\opencv-python\opencv\modules\imgproc\src\color.cpp:182: error: (-215:assertion failed) !_src.empty() in function 'cv::cvtcolor'
By Megan Gerhold at Jun 18 2020