Different MSEs for identical model training runs

I am practising with the Model Evaluation and Selection lab (week 3 of Advanced Machine Learning). I am running the code of the neural network example of model training in a jupyter notebook on my mac laptop. The issue is that I get different MSEs for identical runs, which makes it impossible to compare different models. Can anyone please advise on how to get the model training to yield reproducible results?

I ran the code several times and obtained the same MSE score each time.

Here are the scores for the three models:

Model 1: Training MSE: 73.44, CV MSE: 113.87
Model 2: Training MSE: 73.40, CV MSE: 112.28
Model 3: Training MSE: 44.56, CV MSE: 88.51

Please restart the kernel and re-run all cells. Then, please report back if that works.

Also, check you have not deleted the code which set the random seed, like random.seed(42) or something like that.