WordPress: unregister custom post type registered by plugin "Essential Grid"

functions.php

<?php
/*
 * Use this funtion to delete the custom post type registered by the plugin "Essential Grid"
 * Alternative method to the one proposed by plugin authors:
 * https://www.themepunch.com/faq/hide-ess-grid-posts-custom-post-type-from-wp-main-menu/
 *
 * Usage for other CPT: Replace 'essential_grid' with the slug of the custom post type 
 *
 * Sources: 
 * https://gist.github.com/johnkolbert/769160
 * https://core.trac.wordpress.org/ticket/14761
*/
if ( ! function_exists( 'unregister_post_type' ) ) :
function unregister_post_type() {
    global $wp_post_types;
    if ( isset( $wp_post_types[ 'essential_grid' ] ) ) {
        unset( $wp_post_types[ 'essential_grid' ] );
        return true;
    }
    return false;
}
endif;

add_action('init', 'unregister_post_type',100);
?>