class ActiveAdmin::ResourceController

It implements actions and helpers for resources.
All Resources Controller inherits from this controller.

def self.active_admin_config=(config) 

def self.active_admin_config=(config)
  if @active_admin_config = config
    defaults resource_class: config.resource_class,
             route_prefix: config.route_prefix,
             instance_name: config.resource_name.singular
  end
end

def self.inherited(base)

our resource_class method each time we're inherited from.
in `self.resource_class`. To override it, we need to install
Inherited Resources uses the `self.inherited(base)` hook to add 
def self.inherited(base)
  super(base)
  base.override_resource_class_methods!
end

def renderer_for(action)

Returns the renderer class to use for the given action. 
def renderer_for(action)
  active_admin_namespace.view_factory["#{action}_page"]
end

def restrict_format_access! 

def restrict_format_access!
  unless request.format.html?
    presenter = active_admin_config.get_page_presenter(:index)
    download_formats = (presenter || {}).fetch(:download_links, active_admin_config.namespace.download_links)
    unless build_download_formats(download_formats).include?(request.format.symbol)
      raise ActiveAdmin::AccessDenied.new(current_active_admin_user, :index)
    end
  end
end