Typo in chapter 4: One-Dimensional-Kalman-Filters.ipynb

[lfwin]

Hi,
There is a typo in chapter 4, cell 14,
plt.plot(xs, ys, label='$\mathcal{N}$' + '$({g2.mean},{ge.var})$') should be replaced with
plt.plot(xs, ys, label='$\mathcal{N}$' + f'$({g2.mean},{g2.var})$').
In addition, thanks for sharing such good online free book.