No lambda support

[rockwotj]

The code fragment below is a copy from mustache, but I can't get render object defined for lambda support. The console told me argument render is undefined. Is there something that i misunderstand?

Template:

{{#wrapped}}
     {{name}} is awesome.
{{/wrapped}}

Hash:

{
  "name": "Willy",
    "wrapped": function() {
     return function(text, render) { //render param is undefined
       return "<b>" + render(text) + "<b/>"
    }
  }
}