In Coffeekup how can I call a function from within the template

this is not working for me:

  class Saturn
    test: ->
      "test"

    @ck: null

    htmlTemplate: ->
      @ck.render -> 
        doctype 5
        html ->
          @headerTemplate

    headerTemplate: ->
      @ck.render -> 
        head ->
          meta charset: 'utf-8'
          meta name: 'viewport', content: 'width=device-width'
          title ''
          link rel: 'stylesheet', href: 'css/normalize.css'
          link rel: 'stylesheet', href: 'css/foundation.css'
          script src: 'js/vendor/custom.modernizr.js'

    renderCustomerTransaction: (a) ->
      @ck = require 'coffeekup'
      @htmlTemplate()

I call renderCustomerTransaction(5) and all I get back is

'<!DOCTYPE html><html></html>'

CoffeeScript is not Ruby, you have to explicitely call @headerTemplate : @headerTemplate()