Custom admin menu, page shows child menus in Drupal

Source code viewer
function hook_menu() // don't forget to change hook to your module name
{
  $items = array();
 
  $items['admin/custom-content'] = array(
    'title' => 'Custom content', // menu name
    'description' => 'Custom made configuration pages.', // menu description
    'position' => 'right',
    'page callback' => 'system_admin_menu_block_page',
    'access arguments' => array('access administration pages'),
    'file' => 'system.admin.inc',
    'file path' => 'modules/system',
  );
 
  return $items;
}
Programming Language: PHP