Uses the code "grid(b=true)" in 06-Multivariate-Kalman-Filters.ipynb are generating an error

[LuisGSVasconcelos]

I'm following the book and I think it's very educational and simple to understand. I really think it's a good job. With the aim of contributing to the book I noticed that some graphs in the notebook "06-Multivariate-Kalman-Filters.ipynb" which uses the code "grid(b=true)" are generating an error. I changed the kf_book code to "grid(visible = true)" as per Jupyter's guidance and the problem was resolved.

[fenaux]

I did not get the problem with "06-Multivariate-Kalman-Filters.ipynb" but I got it with "10-Unscented-Kalman-Filter"
To solve it I just commented line 237 and 246 in kf_book/nonliear_plots.py