Feature: PrivateVPN support (#393)

internal/constants/constants.go

@@ -1,3 +1,25 @@
 // Package constants defines constants shared throughout the program.
 // It also defines constant maps and slices using functions.
 package constants
+
+import "sort"
+
+func makeChoicesUnique(choices []string) []string {
+	uniqueChoices := map[string]struct{}{}
+	for _, choice := range choices {
+		uniqueChoices[choice] = struct{}{}
+	}
+
+	uniqueChoicesSlice := make([]string, len(uniqueChoices))
+	i := 0
+	for choice := range uniqueChoices {
+		uniqueChoicesSlice[i] = choice
+		i++
+	}
+
+	sort.Slice(uniqueChoicesSlice, func(i, j int) bool {
+		return uniqueChoicesSlice[i] < uniqueChoicesSlice[j]
+	})
+
+	return uniqueChoicesSlice
+}