public Bank get(Town town) {
   for (Bank bank : this) {
     if (bank.getTown() == town) {
       return bank;
     }
   }
   return null;
 }
 public boolean contains(Town town) {
   for (Bank bank : this) {
     if (bank.getTown() == town) {
       return true;
     }
   }
   return false;
 }