/**
  * Add a new filter to the collection to be registered with WordPress.
  *
  * @since    2.0
  * @see    Switch_User->add_filter
  */
 private function add_filter($hook, $callback, $priority = 10, $accepted_args = 1)
 {
     if ($this->core != null) {
         $this->core->add_filter($hook, $callback, $priority, $accepted_args);
     } else {
         if (WP_DEBUG) {
             trigger_error(__('Core was not passed in "Switch_User_Frontend".'), E_USER_WARNING);
         }
     }
 }
/**
 * Making things happening
 *
 * @since    2.0
 */
function switch_user_starts()
{
    define('SWITCH_USER_VERSION', '2.1');
    define('SWITCH_USER_SCRIPTS_VERSION', '2.1');
    define('SWITCH_USER_TEXTDOMAIN', 'switch-user');
    define('SWITCH_USER_TAG', 'switch_user');
    $plugin = new Switch_User();
    if (SWITCH_USER_TAG == $plugin->class_tag) {
        $plugin->run();
    } else {
        trigger_error(__('The Switch_User was overwritten...'), E_USER_WARNING);
    }
}