public void InsertAccount(Account account)
        {
            if (account is null)
            {
                throw new ArgumentNullException(nameof(account));
            }

            _dbContext.Accounts.Add(account);
            _dbContext.SaveChanges();
        }
        public void InsertTransaction(Transaction transaction)
        {
            if (transaction is null)
            {
                throw new ArgumentNullException(nameof(transaction));
            }

            _dbContext.Transactions.Add(transaction);
            _dbContext.SaveChanges();
        }