如何从torchvision.datasets.CIFAR10中仅提取类的子集？

import torch
import torchvision

classes = ['cat', 'dog']

trainset = torchvision.datasets.CIFAR10(root='./data', train=True, download=True)
testset = torchvision.datasets.CIFAR10(root='./data', train=False, download=True)

train_subset = torch.utils.data.Subset(trainset, [i for i in range(len(trainset)) if trainset.targets[i] in classes])
test_subset = torch.utils.data.Subset(testset, [i for i in range(len(testset)) if testset.targets[i] in classes])

transform = torchvision.transforms.Compose([
    torchvision.transforms.ToTensor(),
    torchvision.transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))
])

train_subset = torchvision.datasets.CIFAR10(root='./data', train=True, download=True, transform=transform)
test_subset = torchvision.datasets.CIFAR10(root='./data', train=False, download=True, transform=transform)

trainloader = torch.utils.data.DataLoader(train_subset, batch_size=64, shuffle=True, num_workers=2)
testloader = torch.utils.data.DataLoader(test_subset, batch_size=64, shuffle=False, num_workers=2)