missing argument error after adding column classes snippet

On the page with the shortcode we get this error, after adding the code for “Add Column Classes to Display Posts Shortcodes”

Here is the shortcode on the page
[display-posts columns=”2″ category=”work” posts_per_page=”6″ image_size=”medium” include_excerpt=”true”]

Here is the error we get
Warning: Missing argument 4 for be_display_post_class() in /home/hsd34dg/public_html/wp-content/plugins/display-posts-shortcode/display-posts-shortcode.php on line 277

https://ww.wp.xz.cn/plugins/display-posts-shortcode/