           "firstName": "Sean",
           "lastName": "Connery"],
       "awards": ["Academy Award", "BAFTA Awards", "Golden Globes"]]
-  let rendering = template.render(Box(data))!
+  template.render(Box(data))!
 
 :see: DidRenderFunction
 :see: Tag


  // Attempt to feed the template with the user produces a compiler error, since
  // User can not be boxed.
  let rendering = template.render(Box(user))!

  // Make User conform to MustacheBoxable
  extension User : MustacheBoxable {

// MARK: - FilterFunction

/**
FilterFunction is the core type that lets GRMustache evaluate filtered
expressions such as {{ uppercase(name) }}.

It turns a MustacheBox to another MustacheBox, and optionally returns an error.
