Fixed wording in bank accounts example.
@@ -25,7 +25,7 @@ The ``BankAccount`` aggregate class is defined using the
:ref:`declarative syntax <Declarative syntax>`. It has a
balance and an overdraft limit. Accounts can be opened and
closed. Accounts can be credited and debited, which affects
-the balance. Neither credits nor debits are not allowed if
+the balance. Neither credits nor debits are allowed if
the account has been closed. Debits are not allowed if the
balance would go below the overdraft limit. The overdraft
limit can be adjusted.
