python opencv    self._model = cv.dnn.readNet(self._model_path)  报错   

```
cv2.error: OpenCV(4.2.0) C:\projects\opencv-python\opencv\modules\dnn\src\dnn.cpp:562: error: 
 (-2:Unspecified error) Can't create layer "76" of type "ConstantOfShape" in function  
'cv::dnn::dnn4_v20191202::LayerData::getLayerInstance'

```

使用  opencv 4.4.0 问题解决    