public function plugin_callback()
 {
     $options = "";
     foreach ($this->plugins as $plugin) {
         //print_r($plugin);
         if (AfterShip_Dependencies::plugin_active_check($plugin['path'])) {
             $option = '<option value="' . $plugin['value'] . '"';
             if (isset($this->options['plugin']) && esc_attr($this->options['plugin']) == $plugin['value']) {
                 $option .= ' selected="selected"';
             }
             $option .= '>' . $plugin['label'] . '</option>';
             $options .= $option;
         }
     }
     printf('<select id="plugin" name="aftership_option_name[plugin]" class="aftership_dropdown">' . $options . '</select>');
 }