Runtime Error in Lesson 2: MatPlotLib? Kwargs?

Part 1 (2019)
1

I am stuck on a runtime error when I run this code from Lesson 2 (SGD Notebook):

plt.scatter(x[:,0],x@a)

For me, it throws multiple errors: https://share.getcloudapp.com/KouWp70y

I have tried this on both Google Collab and Gradient.

Thanks in advance for any help you can give.