code: def variantAnnotationSetsGenerator(self, request):
          
          compoundId = datamodel.VariantSetCompoundId.parse(
              request.variant_set_id)
          dataset = self.getDataRepository().getDataset(compoundId.dataset_id)
          variantSet = dataset.getVariantSet(request.variant_set_id)
          return self._topLevelObjectGenerator(
              request, variantSet.getNumVariantAnnotationSets(),
              variantSet.getVariantAnnotationSetByIndex)
docs: Returns a generator over the (variantAnnotationSet, nextPageToken)
          pairs defined by the specified request.