Question about Task 8

I have a doubt about Task 8: This implementation plots "sumet", while the benchmark says to plot "the transverse mass of the missing energy." Is that the same? I guess it isn't; the [Coffea implementation](https://github.com/mat-adamec/coffea-benchmarks/blob/master/benchmarks/example8.ipynb) computes it as `massT` through `mt_e` and `mt_mu`...