/// <summary>
/// Multiton class.
/// </summary>
private PatternConverter(IAlphabet alphabetSet)
{
_alphabetSet = alphabetSet;
// Generate unique & ambiguous Alphabets list
_alphabets = new HashSet <char>();
_alphabetSet.LookupAll(true, false, false, false).All(amp => _alphabets.Add(amp.Symbol));
}