MX_Loader::plugin PHP Method

    public function plugin($plugin)
    {
        if (is_array($plugin)) {
            return $this->plugins($plugin);
        }
        if (isset($this->_ci_plugins[$plugin])) {
            return $this;
        }
        list($path, $_plugin) = Modules::find($plugin . '_pi', $this->_module, 'plugins/');
        if ($path === FALSE && !is_file($_plugin = APPPATH . 'plugins/' . $_plugin . EXT)) {
            show_error("Unable to locate the plugin file: {$_plugin}");
        }
        Modules::load_file($_plugin, $path);
        $this->_ci_plugins[$plugin] = TRUE;
        return $this;
    }

 function plugin($plugin)
 {
     if (!is_array($plugin)) {
         self::define_module($plugin);
     }
     return parent::plugin($plugin);
 }