plotGeneCount using only one lineage

[Yanst86]

Hi,

Thanks for the great package!
I have a dataset of ~3100 cells with 6 different lineages inferred by Slingshot, however I was interested in only one of them and followed the suggestions in issue #187 to run fitGAM only on cells from the relevant lineage. Does someone have an idea how can I plot only this specific lineage (the default is to plot all) using plotGeneCount?

Thanks,
Yan