左侧的分配无效。 （第1行，文件＆＃34;代码＆＃34;）

Question

以下是我的代码

我的任务是从谷歌脚本发布到Wordpress的帖子

当我尝试以下代码时，我收到了无效分配左侧的错误。 （第1行，文件＆＃34;代码＆＃34;）

请任何人都可以帮助我

 function programmatically_create_post(){

    // Initialize the page ID to -1. This indicates no action has been taken.
    $post_id = (-1);

    // Setup the author, slug, and title for the post
    $author_id = 1;
    $slug = 'example-post';
    $title = 'My Example Post';

    // If the page doesn't already exist, then create it
    if( null == get_page_by_title( $title ) ) {

        // Set the post ID so that we know the post was created successfully
        $post_id = wp_insert_post(
            array(
                'comment_status'    =   'closed',
                'ping_status'       =   'closed',
                'post_author'       =   $author_id,
                'post_name'         =   $slug,
                'post_title'        =   $title,
                'post_status'       =   'publish',
                'post_type'         =   'post'
            )
        );

    // Otherwise, we'll stop
    } else {

            // Arbitrarily use -2 to indicate that the page with the title already exists
            $post_id == (-2);

    } // end if

} // end programmatically_create_post
add_filter( "after_setup_theme", + "programmatically_create_post" );
$post_id = programmatically_create_post()
if( -1 == $post_id || -2 == $post_id ) {
   // The post wasn't created or the page already exists
} // end if