}

func (az *warmBackendAzure) InUse(ctx context.Context) (bool, error) {
	maxResults := int32(1)
	pager := az.clnt.NewListBlobsFlatPager(az.Bucket, &azblob.ListBlobsFlatOptions{
		Prefix:     &az.Prefix,
		MaxResults: &maxResults,
	})
	if !pager.More() {
		return false, nil
	}

	resp, err := pager.NextPage(ctx)
	if err != nil {
		if strings.Contains(err.Error(), "no more pages") {
			return false, nil

	it := gcs.client.Bucket(gcs.Bucket).Objects(ctx, &storage.Query{
		Delimiter: "/",
		Prefix:    gcs.Prefix,
		Versions:  false,
	})
	pager := iterator.NewPager(it, 1, "")
	gcsObjects := make([]*storage.ObjectAttrs, 0)
	_, err := pager.NextPage(&gcsObjects)
	if err != nil {
		return false, gcsToObjectError(err, gcs.Bucket, gcs.Prefix)
	}
	if len(gcsObjects) > 0 {
		return true, nil
	}

*   Adds `beta` hyperparameter to
    [FTRL](https://www.tensorflow.org/api_docs/python/tf/keras/optimizers/Ftrl)
    optimizer classes (Keras and others) to match
    [FTRL paper](https://research.google.com/pubs/archive/41159.pdf).
*   `Optimizer.__init__` now accepts a `gradient_aggregator` to allow for
    customization of how gradients are aggregated across devices, as well as