Optional Labs

I know I should at least understand the concepts and the theories in the optional labs. I know python and maths and going well through the labs.
The question is: do i have to understand the visualization code implemented in matplotlib?
I have no previous exposure to matplotlib, so can i skip them or I must understand them and implement them in order to have better experience in ml?

Not necessarily directly connect to ML but more on the graphical representation of data! Of course it adds extra value if you understand it.