public static void main(String[] argsv) {

        // Setting op a bank.
        Bank christmasBank = new Bank();
        christmasBank.addAccount(new BankAccount(BigInteger.valueOf(100)));
        christmasBank.addAccount(new BankAccount(BigInteger.valueOf(50), BigInteger.valueOf(-1000)));

        // Print the balance of all accounts with a balance not below some threshold.
//        System.out.print("Enter the threshold for the balance: ");
//        Scanner inputStreamScanner = new Scanner(System.in);
//        BigInteger threshold = BigInteger.valueOf(inputStreamScanner.nextLong());

        Set<BankAccount> accountsBalanceNotBelowThreshold =
                christmasBank.getAccountsSatisfying(
                        new Checker<BankAccount>() {
                            public boolean check(BankAccount account) {
                                return (account.getBalance().compareTo(BigInteger.valueOf(70)) >= 0);
                            }
                        });
        for (BankAccount account: accountsBalanceNotBelowThreshold)
            System.out.println(account.getBalance());

    }