At least two classes are needed to perform a LDA

[Sagehill]

OpenCV(4.5.1) C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-i1s8y2i1\opencv\modules\core\src\lda.cpp:1087: error: (-5:Bad argument) At least two classes are needed to perform a LDA. Reason: Only one class was given! in function 'cv::LDA::lda'