def removeCallback(service, nodeIdentifier, callback):
    """
        Remove a registered callback URI.

        The returned deferred will fire with a boolean that signals wether or
        not this was the last callback unregistered for this node.

        @param service: The XMPP entity that holds the node.
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}
        @param nodeIdentifier: The identifier of the publish-subscribe node.
        @type nodeIdentifier: C{unicode}.
        @param callback: The callback URI to be unregistered.
        @type callback: C{str}.
        @rtype: L{Deferred<twisted.internet.defer.Deferred>}
        """
