---
layout: docs
title: __construct
id: class.Facebook.HackCodegen._Private.HackBuilderKeyLambdaRenderer.__construct
docid: class.Facebook.HackCodegen._Private.HackBuilderKeyLambdaRenderer.__construct
permalink: /docs/reference/class.Facebook.HackCodegen._Private.HackBuilderKeyLambdaRenderer.__construct/
---
# Facebook\\HackCodegen\\_Private\\HackBuilderKeyLambdaRenderer::__construct()




``` Hack
public function __construct(
  callable $callback,
);
```




## Parameters




- ` callable $callback `