def subscribe(service, nodeIdentifier, subscriber):
    """
        Subscribe to a node with a given JID.

        @param service: The publish-subscribe service entity.
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}
        @param nodeIdentifier: Identifier of the node to subscribe to.
        @type nodeIdentifier: C{unicode}
        @param subscriber: JID to subscribe to the node.
        @type subscriber: L{JID<twisted.words.protocols.jabber.jid.JID>}
        @rtype: L{Deferred<twisted.internet.defer.Deferred>}
        """
