我在自定义构建模板中显示变体时遇到问题，每次我在循环中调用wpsc函数wpsc_have_variation_groups()时，我都会收到以下php错误commerce/wpsc-includes/product-template.phponline1419[22-Nov-201223:27:39]PHPfatalerror:调用成员函数have_variation_groups()/home/tofapost/public_html/sandbox/wp/wp-content/plugins/wp-e-commerce/wpsc-includes/product-template.