code: def annotate(self, **kwargs) -> "QuerySet":
          
          queryset = self._clone()
          for key, aggregation in kwargs.items():
              if not isinstance(aggregation, Aggregate):
                  raise TypeError("value is expected to be Aggregate instance")
              queryset._annotations[key] = aggregation
              from tortoise.models import get_filters_for_field
  
              queryset._custom_filters.update(get_filters_for_field(key, None, key))
          return queryset
docs: Annotate result with aggregation result.