Something

    def load(self):

        # Enumerate provider modules

        get_providermodules = EnumerateInstances(
            ('root', 'penguin'), 'PG_ProviderModule', 
            namespace = 'root/PG_InterOp')

        get_providermodules.deferred.addCallbacks(
            lambda result: setattr(self, 'providermodules', result), error_cb)

        reactor.connectTCP(HOSTNAME, 5988, get_providermodules)

        # Enumerate providers

        get_providers = EnumerateInstances(
            ('root', 'penguin'), 'PG_Provider', namespace = 'root/PG_InterOp')

        get_providers.deferred.addCallbacks(
            lambda result: setattr(self, 'providers', result), error_cb)

        reactor.connectTCP(HOSTNAME, 5988, get_providers)

        # Enumerate provider capabilities

        get_providercaps = EnumerateInstances(
            ('root', 'penguin'), 'PG_ProviderCapabilities',
            namespace = 'root/PG_InterOp')

        get_providercaps.deferred.addCallbacks(
            lambda result: setattr(self, 'providercaps', result), error_cb)

        reactor.connectTCP(HOSTNAME, 5988, get_providercaps)

        dl = DeferredList([get_providers.deferred,
                           get_providermodules.deferred,
                           get_providercaps.deferred])
        
        dl.addCallback(self.handle_results_cb)