Is this a Potential code error or machine set up error? Not sure

I am working through section 19.2.3 of HOML/autoencoders.html and found an error message pop up.

In section: 19.2.3 Visualizing the reconstruction, I found an error associated with the line:

# Predict reconstructed pixel values  
best_model_id <- grid_perf@model_ids[[1]]

after this line I get:

Error: object 'grid_perf' not found

Up to this point, I have followed the code from the Autoencoder section, should I look at my setup or is this a change in H2O.ai and code?

HTH