Does showtext package in R allow fontfaces other than regular, bold and italic?

Question

I'm trying to use different fontfaces for a plot, I'm using showtext to load the font.

Working code goes:

library("tidyverse")
library("showtext")

font_add(family = "nutmeg", regular = "/nutmeg/Nutmeg-Regular.ttf", 
         bold = "/nutmeg/Nutmeg-Bold.ttf")
showtext.auto()

However, when trying to add, for example, a light fontface:

library("tidyverse")
library("showtext")

font_add(family = "nutmeg", regular = "/nutmeg/Nutmeg-Regular.ttf", 
         bold = "/nutmeg/Nutmeg-Bold.ttf", light = "/nutmeg/Nutmeg-Light.ttf")
showtext.auto()

I get the error: Error in font_add(family = "nutmeg", regular = "/nutmeg/Nutmeg-Regular.ttf", : unused argument (light = "/nutmeg/Nutmeg-Light.ttf")

I'm guessing showtext doesn't support fontfaces other than Regular, Bold and Italic. Is there a way to work around this? Please try to dumb it down, I'm really new at using R. Thanks!