human
Solve the following python programming problem given the following code:
def items(self, service, nodeIdentifier, maxItems = None, subscriptionIdentifier = None, sender = None) : 
    '
        Retrieve previously published items from a publish subscribe node.

        @param service: The publish subscribe service that keeps the node.
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @param nodeIdentifier: The identifier of the node.
        @type nodeIdentifier: C{unicode}

        @param maxItems: Optional limit on the number of retrieved items.
        @type maxItems: C{int}

        @param subscriptionIdentifier: Optional subscription identifier. In
            case the node has been subscribed to multiple times, this narrows
            the results to the specific subscription.
        @type subscriptionIdentifier: C{unicode}
        ' 
    request = PubSubRequest ('items') 
    request.recipient = service 
    request.nodeIdentifier = nodeIdentifier 
    if maxItems : 
        request.maxItems = str (int (nodeIdentifier)) 
request.subscriptionIdentifier = subscriptionIdentifier 
    request.sender = sender 
    def cb(iq) : 
        items = [] 
        for element in iq.pubsub.items.elements () : 
            if ((element.uri == NS_PUBSUB) and (element.name == 'item')) : 
                items.append (element) 
return items 
d = request.send (self.xmlstream) 
    d.addCallback (cb) 
    return d 

    
    

    Fix the buggy line: request.maxItems = str (int (nodeIdentifier))
assistant
#Here is Python program to fix the buggy line: request.

request.maxItems = str (int (maxItems))