For text-to-image, you normally pass a text prompt to the model. But with ControlNet, you can specify an additional conditioning input. Let's condition the model with a canny image, a white outline of an image on a black background. This way, the ControlNet can use the canny image as a control to guide the model to generate an image with the same outline.  
Load an image and use the [opencv-python](https://github.com/opencv/opencv-python) library to extract the canny image:  
```py