UpdateSubscription.
        [Preview API] Update an existing subscription. Depending on the type of subscription and permissions, the caller can update the description, filter settings, channel (delivery) settings and more.
        :param :class:`<NotificationSubscriptionUpdateParameters> <azure.devops.v5_0.notification.models.NotificationSubscriptionUpdateParameters>` update_parameters:
        :param str subscription_id:
        :rtype: :class:`<NotificationSubscription> <azure.devops.v5_0.notification.models.NotificationSubscription>`

def update_subscription(self, update_parameters, subscription_id):
        """UpdateSubscription.
        [Preview API] Update an existing subscription. Depending on the type of subscription and permissions, the caller can update the description, filter settings, channel (delivery) settings and more.
        :param :class:`<NotificationSubscriptionUpdateParameters> <azure.devops.v5_0.notification.models.NotificationSubscriptionUpdateParameters>` update_parameters:
        :param str subscription_id:
        :rtype: :class:`<NotificationSubscription> <azure.devops.v5_0.notification.models.NotificationSubscription>`
        """
        route_values = {}
        if subscription_id is not None:
            route_values['subscriptionId'] = self._serialize.url('subscription_id', subscription_id, 'str')
        content = self._serialize.body(update_parameters, 'NotificationSubscriptionUpdateParameters')
        response = self._send(http_method='PATCH',
                              location_id='70f911d6-abac-488c-85b3-a206bf57e165',
                              version='5.0-preview.1',
                              route_values=route_values,
                              content=content)
        return self._deserialize('NotificationSubscription', response)