if (FALSE)
  getCountries("nordic")

getCountries <- function(group, DT.country) {
  dict.region_groups <- getCountryGroupDict()
  group %<>% tolower %>% match.arg(choices=names(dict.region_groups))

  return(dict.region_groups[[group]])
}

getCountryGroupDict <- function() {
  list(
         nordic = c("Denmark"="DK", "Finland"="FI", "Iceland"="IS", "Norway"="NO", "Sweden"="SE")
  , scandinavia = c("Denmark"="DK", "Finland"="FI",                 "Norway"="NO", "Sweden"="SE")
  )
}