How to perform the cross validation?

hi, anyone can help me how to implement the cross validation in CNN. i have no idea how to implement the cross validation in pytorch.here is my train and test loaders.

trainset = torchvision.datasets.ImageFolder(root='./train', transform=transform) 
trainloader = torch.utils.data.DataLoader(trainset, batch_size=4,
                                          shuffle=True)

testset = torchvision.datasets.ImageFolder(root='./test', transform=transform)
testloader = torch.utils.data.DataLoader(testset, batch_size=4, shuffle=False)

Have you looked into this post?