code: public PubSub modifySubscriptionsAsOwner(List<Subscription> changedSubs)
          throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
  
          PubSub pubSub = createPubsubPacket(Type.set,
              new SubscriptionsExtension(SubscriptionsNamespace.owner, getId(), changedSubs));
          return sendPubsubPacket(pubSub);
      }
docs: Modify the subscriptions for this PubSub node as owner.
  <p>
  Note that the subscriptions are _not_ checked against the existing subscriptions
  since these are not cached (and indeed could change asynchronously)
  </p>
  
  @param changedSubs subscriptions that have changed
  @return <code>null</code> or a PubSub stanza with additional information on success.
  @throws NoResponseException
  @throws XMPPErrorException
  @throws NotConnectedException
  @throws InterruptedException
  @see <a href="https://xmpp.org/extensions/xep-0060.html#owner-subscriptions-modify">XEP-60 § 8.8.2 Modify Subscriptions</a>
  @since 4.3