New D3 module: is it buggy or am i?

Am i just not catching on or is something buggy with the new D3 module on beta. It seems as though I have the correct input for various lessons yet it says “try again”. has anyone else experienced this or am I just not understanding d3 syntax somehow. you can see the graph is drawn yet i get an error??

I have found a trick to get by some of these bugs. All you have to do sometimes is reload the page. Since, the site saves what you have entered, which is cool, it will be there. often times doing this gets you through with a brownie point. it is nice to confirm that one is getting things right. I wonder if this is a universal bug or if it something with my system??

as i continue along the module reloading is working. the ctrl enter runs the test but reloading actually renders what code is in the window. i gotta say this whole site is remarkable.

ALSO. I have realized that I have to at least run tests once before reloading for the site to save my input. then I can click the screen outside of the success modal and play with the d3 graph that i created.