See also the
Braintree_Subscription response object.
If you want to look up a single subscription using its ID, use the
$subscription = Braintree_Subscription::find('a_subscription_id');
If the subscription cannot be found, you'll receive a
The value used to identify a specific subscription. If you do not specify an ID when creating a subscription, the gateway will generate a 6- or 7-character alphanumeric ID. When updating a subscription, you can only use tokens associated with the same customer that the subscription is currently associated with. Once canceled, a subscription cannot be edited or reactivated. You must create a new subscription.