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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def enable_notifications(self, enabled=True):
 """ Enables or disables value change notifications. Success or failure will be notified by calls to `characteristic_enable_notifications_succeeded` or `enable_notifications_failed` respectively. Each time when the device notifies a new value, `characteristic_value_updated()` of the related device will be called. """

        try:
            if enabled:
                self._object.StartNotify(
                    reply_handler=self._enable_notifications_succeeded,
                    error_handler=self._enable_notifications_failed,
                    dbus_interface='org.bluez.GattCharacteristic1')
            else:
                self._object.StopNotify(
                    reply_handler=self._enable_notifications_succeeded,
                    error_handler=self._enable_notifications_failed,
                    dbus_interface='org.bluez.GattCharacteristic1')
        except dbus.exceptions.DBusException as e:
            self._enable_notifications_failed(error=e)