code: def change_node_subscriptions(self, jid, node, subscriptions_to_set):
          
          iq = aioxmpp.stanza.IQ(
              type_=aioxmpp.structs.IQType.SET,
              to=jid,
              payload=pubsub_xso.OwnerRequest(
                  pubsub_xso.OwnerSubscriptions(
                      node,
                      subscriptions=[
                          pubsub_xso.OwnerSubscription(
                              jid,
                              subscription
                          )
                          for jid, subscription in subscriptions_to_set
                      ]
                  )
              )
          )
  
          yield from self.client.send(iq)
docs: Update the subscriptions at a node.
  
          :param jid: Address of the PubSub service.
          :type jid: :class:`aioxmpp.JID`
          :param node: Name of the node to modify
          :type node: :class:`str`
          :param subscriptions_to_set: The subscriptions to set at the node.
          :type subscriptions_to_set: :class:`~collections.abc.Iterable` of
              tuples consisting of the JID to (un)subscribe and the subscription
              level to use.
          :raises aioxmpp.errors.XMPPError: as returned by the service
  
          `subscriptions_to_set` must be an iterable of pairs (`jid`,
          `subscription`), where the `jid` indicates the JID for which the
          `subscription` is to be set.