def METHOD_NAME(self, subscriber_id):
    """
    Context Manager to update the subscriber data.
    Provides the subscriber data as the context, and the underlying
    store guarantees the update to be atomic (by doing the
    necessary locking).
    Args:
        subscriber_id - unique identifier for the subscriber
    Raises:
        SubscriberNotFoundError if the subscriber is not present
    """
    raise NotImplementedError()