         respond(response)
     }
     
-    private func executeWriteRequest(_ pdu: ATTExecuteWriteRequest) {
+    private func executeWriteRequest(pdu: ATTExecuteWriteRequest) {
         
         let opcode = pdu.dynamicType.attributeOpcode
         

        let newData = Data(byteValue: value)
        
        // validate application errors with write callback
        if let error = willWrite?(UUID: attribute.UUID, value: attribute.value, newValue: (newData, newData, 0)) {
            
            doResponse(errorResponse(opcode, error, handle))
            return

            
        case .Write:
            
            var newValues = [UInt16: Data]()
            
            // validate
            for write in preparedWrites {
                
                let previousValue = newValues[write.handle] ?? Data()
                
                let newValue = previousValue.byteValue + write.value
                
                // validate offset?
                
                newValues[write.handle] = Data(byteValue: newValue)
            }
            
            // validate new values
            for (handle, newValue) in newValues {
                
                let attribute = database[handle]
                
                // validate application errors with write callback
                if let error = willWrite?(UUID: attribute.UUID, value: attribute.value, newValue: newValue) {
                    
                    errorResponse(opcode, error, handle)
                    return
                }
            }
            
            // write new values
            for (handle, newValue) in newValues {
                
                database.write(newValue, forAttribute: handle)
            }
            
        case .Cancel: break // queue always cleared
