/// <summary>
 /// Add phone number only if good value
 /// </summary>
 public void Add(long number, PhoneNumber.Types type)
 {
     // number must at least be 000-1000
     if (number >= 10000)
     {
         this.Add(new PhoneNumber(number, type));
     }
 }
 /// <summary>
 /// The first instance of a type of number
 /// </summary>
 public PhoneNumber this[PhoneNumber.Types type] {
     get {
         foreach (PhoneNumber p in this)
         {
             if (p.Type == type)
             {
                 return(p);
             }
         }
         return(null);
     }
 }