Prevent ACF Pro license key from being overwritten during WP Migrate DB Pro migration

acf-migrate-db-pro.php

<?php
/*
Based on http://github.com/deliciousbrains/wp-migrate-db-pro-tweaks
*/

class ACF_WP_Migrate_DB_Pro_Tweaks {
	function __construct() {
		add_filter( 'wpmdb_preserved_options', array( $this, 'preserved_options' ) );
	}

	/**
	 * By default, 'wpmdb_settings' and 'wpmdb_error_log' are preserved when the database is overwritten in a migration.
	 * This filter allows you to define additional options (from wp_options) to preserve during a migration.
	 * The example below preserves the 'blogname' value though any number of additional options may be added.
	 */
	function preserved_options( $options ) {
		$options[] = 'acf_pro_license';
		return $options;
	}
}

new ACF_WP_Migrate_DB_Pro_Tweaks();

This may be a stupid question but where do you place the code? I've tired placing it in my functions.php file but it doesn't seem to work. I'm also assuming I don't need to add my license to the $options value but just wanted to double check.

Issue resolved. I realized I needed to have the code on both the local and production sites for it to work.