Getting error while ploting ROC for multiclass classification

I am trying to plot ROC Curve for multiclass classification.I followed https://scikit-learn.org/stable/auto_examples/model_selection/plot_roc.html.
I used the below code to calculate y_test,and y_score

def test_epoch(net,test_loader):
 y_test =[]
 y_score =[]
 with torch.no_grad():
  for batch in test_loader:
    images, labels = batch['image'], batch['grade']
    images =Variable(images)
    labels= Variable(labels)
    outputs = net(images)
    _, predicted = torch.max(outputs.data, 1)
    c = (predicted == labels).squeeze().numpy()
    y_score.append(outputs.numpy())
    y_test.append(labels.numpy())
    return y_test,y_score    `  

I seen that my y_test is array like below [array([0, 4, 0, 2, 1, 0, 0, 3, 0, 1, 1, 0, 3, 2, 0, 2, 2, 2, 1, 1, 1, 0,0, 0, 0, 3, 0, 0, 0, 4, 2, 1, 2, 0, 2, 1, 0, 4, 0, 0, 0, 1, 2, 2 0, 1, 2, 2, 0, 2, 0, 2, 2, 3, 2, 3, 3, 1, 1, 1, 0, 2, 0, 0, 2, 1,3, 0, 2, 0, 3, 2, 1, 0, 2, 2, 1, 0, 0, 0, 0, 2, 1, 2, 0, 3, 0, 1, 3, 0, 3, 2, 0, 3, 1, 0, 1, 2, 2, 0])]
And y_score is like[array([[ 0.30480504, -0.12213976, 0.09632117, -0.16465648, -0.44081157],[ 0.21797988, -0.09650452, 0.07616544, -0.12001953, -0.34972644],[ 0.3230184 , -0.13098559, 0.10277118, -0.17656785, -0.45888817],[ 0.38143447, -0.15880316, 0.12123139, -0.21719441, -0.5281661 ],[ 0.3427343 , -0.13945231, 0.11076729, -0.19657779, -0.4913683 ],

Whenever I called the function for plotting ROC

fpr = dict()
tpr = dict()
roc_auc = dict()
for i in range(N_classes):
    fpr[i], tpr[i], _ = roc_curve(truth_val[:, i],preds_val[:, i])
    roc_auc[i] = auc(fpr[i], tpr[i])
# Compute micro-average ROC curve and ROC area
fpr["micro"], tpr["micro"], _ = roc_curve(truth_val.ravel(), preds_val.ravel())
roc_auc["micro"] = auc(fpr["micro"], tpr["micro"]

I am getting this error massages,Traceback (most recent call last): File "/home/Downloads/demo 3.py", line 435, in <module> plot_roc(y_test, y_score, 5) fpr[i], tpr[i], _ = roc_curve(truth_val[:, i],preds_val[:, i]) TypeError: list indices must be integers or slices, not tuple

I could not understand how I will solve this problem.
I am highly appreciate any kind of help regarding this issue.

Based on the error I think truth_val[:, i] or preds_val[:, i] is a python list ?