Restricting Authors to View Only Posts They Created

functions.php

//Restricting Authors to View Only Posts They Created
//https://www.isitwp.com/restricting-authors-to-view-only-posts-they-created/
function posts_for_current_author($query) {
        global $pagenow;
  
    if( 'edit.php' != $pagenow || !$query->is_admin )
        return $query;
  
    if( !current_user_can( 'manage_options' ) ) {
       global $user_ID;
       $query->set('author', $user_ID );
     }
     return $query;
}
add_filter('pre_get_posts', 'posts_for_current_author');