Other arguments passed on to
discrete_scale to control name, limits,
breaks, labels and so forth.
palette
Palette name. One of
[results=rd,stage=build]{ggthemes:::charopts(c(names(ggthemes::ggthemes_data$tableau$colors),
c("tableau10", "tableau10light", "purplegray6",
"bluered6", "greenorange6")))}.