我想按自定义帖子类型和自定义分类术语筛选搜索结果，结果如下：

add_action(\'pre_get_posts\',\'search_filter\');
function search_filter($query) {
    if($query->query_vars[\'s\'] != \'\' && is_search())
    {
        $query->set(\'post_type\', array(\'partner\',\'event\',\'product\'));
        $tax_query = array(
            \'relation\' => \'OR\',
            array(
                \'taxonomy\' => \'city\',
                \'field\'    => \'slug\',
                \'terms\'    => array( \'belgrade\' )
            )
        );
        $query->set( \'tax_query\', $tax_query );
    }
}