How to use the @here/olp-sdk-dataservice-api.BlobApi.getBlob function in @here/olp-sdk-dataservice-api

private async downloadPartition(
        dataHandle: string,
        abortSignal?: AbortSignal
    ): Promise {
        const builder = await this.getRequestBuilder("blob", abortSignal);
        return BlobApi.getBlob(builder, {
            dataHandle,
            layerId: this.layerId
        }).catch(this.errorHandler);
    }

private async downloadTile(
        dataHandle: string,
        abortSignal?: AbortSignal
    ): Promise {
        const builder = await this.getRequestBuilder("blob", abortSignal);
        return BlobApi.getBlob(builder, {
            dataHandle,
            layerId: this.layerId
        }).catch(async error => Promise.reject(error));
    }