text: public virtual DescribePlacementGroupsResponse DescribePlacementGroups(DescribePlacementGroupsRequest request){var options = new InvokeOptions();options.RequestMarshaller = DescribePlacementGroupsRequestMarshaller.Instance;options.ResponseUnmarshaller = DescribePlacementGroupsResponseUnmarshaller.Instance;return Invoke<DescribePlacementGroupsResponse>(request, options);}