function wt4u_tasks_admin_notice() {
 $all_tasks_args = array(
  'post_type' => 'post',
  'posts_per_page' => '9999',
 );
 $all_tasks_query = new WP_Query( $all_tasks_args );
 $all_tasks_count = 0;
 if ( $all_tasks_query->have_posts() ) {
  while ( $all_tasks_query->have_posts() ) {
   $all_tasks_query->the_post();
  }
  wp_reset_postdata();
 }
}
add_action('admin_notices', 'wt4u_tasks_admin_notice');