// getUploadSeries returns the supplied series with duplicates removed if
// non-empty; otherwise it returns a default list of series we should
// probably upload, based on cfg.
func getUploadSeries(cfg *config.Config, series []string) []string {
unique := set.NewStrings(series...)
if unique.IsEmpty() {
unique.Add(version.Current.Series)
unique.Add(config.DefaultSeries)
unique.Add(cfg.DefaultSeries())
}
return unique.Values()
}