def setConfiguration(requestor, service, nodeIdentifier, options):
    """
        Called when a node configuration change request has been received.

        @param requestor: The entity the request originated from.
        @type requestor: L{JID<twisted.words.protocols.jabber.jid.JID>}
        @param service: The entity the request was addressed to.
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}
        @param nodeIdentifier: The identifier of the node to change the
                               configuration of.
        @type nodeIdentifier: C{unicode}
        @return: A deferred that fires with C{None} when the node's
                 configuration has been changed.
        @rtype: L{Deferred<twisted.internet.defer.Deferred>}
        """
