仍在通过视频教程https://www.youtube.com/watch?v=weQ5pShEVic&list=PLbMqOoYQ3Mxw1Sl5iAAV4SJmvnAGAhFvK&index=2关于pytorch的工作，但遇到另一个错误。

lossFunc = torch.nn.MSELoss()
for i in range(epoch):
        output = net(x)
        loss = lossFunc(output, y)
        loss.zero_grad()
        loss.backward()
 
        
        for f in net.parameters():
            f.data.sub_(learning_rate = f.grad.data)
print(output, loss)

创建了网络、损失函数，并希望在反向传播之前进行迭代
但得到以下错误：

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
/var/folders/v_/yq26pm194xj5ckqy8p_njwc00000gn/T/ipykernel_9995/2476130544.py in <module>
      3         output = net(x)
      4         loss = lossFunc(output, y)
----> 5         loss.zero_grad()
      6         loss.backward()
      7 

AttributeError: 'Tensor' object has no attribute 'zero_grad'

怎么回事？