Modifying ViT to include 4th channel


I have a series of image data with RGB channels, but I have also added another channel containing a segmentation output that could potentially help the model with the classification task I am working on. I am utilizing the code from the image classification github (link) to get started, but I notice that it takes 3-channel images. How would I begin to modify the code to take in a 4-channel image?

I appreciate any advice or help!