How to add confusion matrix

Hello all,

In Lesson 1 code, at the beginning we have the first run of the model with this code:
data = ImageClassifierData.from_paths(PATH, tfms=tfms_from_model(arch, sz))
learn = ConvLearner.pretrained(arch, data, precompute=True), 3)

I wanted to see the confusion matrix after running this first code, so I used the confusion matrix code towards the end of lesson one and copied it over like this, just after the above code:

log_preds,y = learn.TTA()
probs = np.mean(np.exp(log_preds),0)

preds = np.argmax(probs, axis=1)
probs = probs[:,1]

from sklearn.metrics import confusion_matrix
cm = confusion_matrix(y, preds)

plot_confusion_matrix(cm, data.classes)

It seems to work, at least there are no error messages, but is this correct ?