module ActionView::Layouts

def _default_layout(require_layout = false)

* template - The template object for the default layout (or nil)
==== Returns

an ArgumentError exception is raised (defaults to false)
* require_layout - If set to true and layout is not found,
==== Parameters

Optionally raises an exception if the layout could not be found.
Returns the default layout for this controller. 
def _default_layout(require_layout = false)
  begin
    value = _layout if action_has_layout?
  rescue NameError => e
    raise e, "Could not render layout: #{e.message}"
  end
  if require_layout && action_has_layout? && !value
    raise ArgumentError,
      "There was no default layout for #{self.class} in #{view_paths.inspect}"
  end
  _normalize_layout(value)
end