extension Storage { private static let volumeSamplesCollection = "LokiVolumeSamplesCollection" public func getVolumeSamples(for attachment: String) -> [Float]? { var result: [Float]? Storage.read { transaction in result = transaction.object(forKey: attachment, inCollection: Storage.volumeSamplesCollection) as? [Float] } return result } public func setVolumeSamples(for attachment: String, to volumeSamples: [Float], using transaction: Any) { (transaction as! YapDatabaseReadWriteTransaction).setObject(volumeSamples, forKey: attachment, inCollection: Storage.volumeSamplesCollection) } }