/// <summary>
 /// Complements the specified character in this set.  The character
 /// will be removed if it is in this set, or will be added if it is
 /// not in this set.
 /// </summary>
 /// <draft>ICU4N 60.1</draft>
 /// <provisional>This API might change or be removed in a future release.</provisional>
 public static UnicodeSet Complement(this UnicodeSet set, int c)
 {
     if (set == null)
     {
         throw new ArgumentNullException(nameof(set));
     }
     return(set.Complement(c));
 }