A character string. the colours of choice, current options are
"main", "light" and "misc" for mixed colours as well as "purple", "turquoise",
"blue", "magenta", "brown", "misc", "green", and "red".
reverse
Logical, defaults to FALSE. Should the palette be reversed.
n
Number of colours desired. If a specific value is given which corresponds
to the length of a palette used in the 2019 WHO TB report, this palette is returned,
else the number of entries in the palette with the most colour options (up to its
full length) is returned. Defaults to NULL which returns the longest palette.
add_missings
Add a grey and white colour to the palette, defaults to FALSE.