WordPress Gutenberg block use only once

blocks.php

<?php 

// ... the rest of your file here

  acf_register_block_type(array(
    'name'              => 'hero',
    'title'             => __('Hero'),
    'description'       => __('A custom hero block.'),
    'render_template'   => 'template-parts/blocks/hero/hero.php',
    'category'          => 'formatting',
    'supports' 			=> array( 'align' => false, 'multiple' => false ),
  ));

// ... the rest of your file here

?>