code: function render(template, locals, layoutTemplates, cb) {
      if (!layoutTemplates) layoutTemplates = [];
  
      // We'll render templates from bottom to top of the stack, each template
      // being passed the rendered string of the previous ones as `body`
      var i = layoutTemplates.length - 1;
  
      var _stackRenderer = function(err, htmlStr) {
        if (err) return cb(err);
  
        if (i >= 0) {
          locals.body = htmlStr;
          renderTemplate(layoutTemplates[i--], locals, _stackRenderer);
        } else {
          cb(null, htmlStr);
        }
      };
  
      // Start the rendering with the innermost page template
      renderTemplate(template, locals, _stackRenderer);
    }
docs: Renders `template` with an optional set of nested `layoutTemplates` using
  data in `locals`.