KeyPressed event trigger arguments value is null

When you log in to the handler value, it is null. When setting the IsHandled property the error occurs:

Error message: Uncaught TypeError: Cannot set property 'IsHandled' of undefined

Source code

    var Observable = require('FuseJS/Observable');
    var textValue = Observable();

    var onKeyPress = function(node, handler){
      console.log(JSON.stringify(node), handler);
      console.log("onKeyPress", JSON.stringify(textValue));
      //Handler is null 
      handler.IsHandled = false; 

    module.exports = {

  <TextBox ux:Class="Input" TextColor="Black" Background="#ffffff" PlaceholderColor="Gray" Margin="5"/>

    <Input PlaceholderText="Insert Value" Value="{textValue}" KeyPressed="{onKeyPress}"/>
Fuse version 0.33.0 (build 10195)
Operating system version: Windows 10.