/**
  * Create and return the class object.
  *
  * @access  public
  * @static
  * @since   1.0.0
  */
 public static function get_instance()
 {
     if (is_null(self::$instance)) {
         self::$instance = new Charitable_Extension_Boilerplate_Admin();
     }
     return self::$instance;
 }
<?php

/**
 * Charitable Extension Boilerplate admin hooks.
 *
 * @package     Charitable Extension Boilerplate/Functions/Admin
 * @version     1.0.0
 * @author      Eric Daams
 * @copyright   Copyright (c) 2016, Studio 164a
 * @license     http://opensource.org/licenses/gpl-2.0.php GNU Public License
 */
if (!defined('ABSPATH')) {
    exit;
}
// Exit if accessed directly
/**
 * Add a direct link to the Extensions settings page from the plugin row.
 *
 * @see     Charitable_Extension_Boilerplate_Admin::add_plugin_action_links()
 */
add_filter('plugin_action_links_' . plugin_basename(charitable_extension_boilerplate()->get_path()), array(Charitable_Extension_Boilerplate_Admin::get_instance(), 'add_plugin_action_links'));
/**
 * Add a "Extension Boilerplate" section to the Extensions settings area of Charitable.
 *
 * @see Charitable_Extension_Boilerplate_Admin::add_extension_boilerplate_settings()
 */
add_filter('charitable_settings_tab_fields_extensions', array(Charitable_Extension_Boilerplate_Admin::get_instance(), 'add_extension_boilerplate_settings'), 6);