private static IParticipant GetOrAddParticipantIfMissing(IGameBuilder gameBuilder, Dictionary <IIdentifier, IParticipant> participantDictionary, IIdentifier participantIdentifier)
{
if (!participantDictionary.ContainsKey(participantIdentifier))
{
IParticipant student = gameBuilder.CreateParticipant(participantIdentifier);
participantDictionary.Add(participantIdentifier, student);
student.Sign();
}
return(participantDictionary[participantIdentifier]);
}