public async Task <IReadOnlyList <DataDeliveryReceiptDetails> > BrowseAsync(Keccak?depositId = null, Keccak?dataAssetId = null, Keccak?sessionId = null) { var receipts = Receipts.AsQueryable(); if (!(depositId is null)) { receipts = receipts.Where(c => c.DepositId == depositId); } if (!(dataAssetId is null)) { receipts = receipts.Where(c => c.DataAssetId == dataAssetId); } if (!(sessionId is null)) { receipts = receipts.Where(c => c.SessionId == sessionId); } return(await receipts.OrderBy(s => s.Number).ToListAsync()); }