WordPress で記事詳細ページのテンプレートをカスタマイズする方法

add_action('template_include', 'load_single_template');
 function load_single_template($template) {
     $new_template = '';
    // single post template    
    if( is_single() ) {      
    global $post;
     // 'wordpress' is category slugs      
     if( has_term('wordpress', 'category', $post) ) {        
     // use template file single-wordpress.php        
     $new_template = locate_template(array('single-wordpress.php' ));
           }
          }    
           return ('' != $new_template) ? $new_template : $template;  
           }