code: function(node, jid, subid, success, error) {
          var that = this._connection;
          var iqid = that.getUniqueId("pubsubunsubscribenode");
  
          var iq = $iq({from:this.jid, to:this.service, type:'set', id:iqid})
            .c('pubsub', { xmlns:Strophe.NS.PUBSUB })
            .c('unsubscribe', {'node':node, 'jid':jid});
          if (subid) iq.attrs({subid:subid});
  
          that.sendIQ(iq.tree(), success, error);
          this.removeHandler(node);
          return iqid;
      }
docs: *Function
  Unsubscribe from a node.
  
  Parameters:
  (String) node       - The name of the pubsub node.
  (Function) success  - callback function for successful node creation.
  (Function) error    - error callback function.