public bool AddPerson(string email, string name, int age, string town)
{
if (peopleByEmail.ContainsKey(email))
{
return(false);
}
Person person = new Person(email, name, age, town);
peopleByEmail.Add(email, person);
string emailDomain = this.ExtractEmailDomain(email);
peopleByEmailDomain.AppendValueToKey(emailDomain, person);
peopleByNameAndTown.AppendValueToKey(new Tuple <string, string>(name, town), person);
peopleByAge.AppendValueToKey(age, person);
this.peopleByTownAndAge.EnsureKeyExists(town);
this.peopleByTownAndAge[town].AppendValueToKey(age, person);
return(true);
}