public function get_products( $post_type = 'any' ) {

		global $wpdb;

		$table = $this->get_product_to_voucher_table_name();

		$products = $wpdb->get_col( $wpdb->prepare( "SELECT product_id FROM {$table} WHERE `voucher_id` = %d;", $this->id ) ); //phpcs:disable WordPress.DB.PreparedSQL.InterpolatedNotPrepared

		if ( ! empty( $products ) ) {

			// Filter any products that don't match the supplied post type.
			if ( 'any' !== $post_type ) {
				foreach ( $products as $i => $id ) {
					if ( get_post_type( $id ) !== $post_type ) {
						unset( $products[ $i ] );
					}
				}
			}

			// Convert all elements to ints.
			$products = array_map( 'intval', $products );

		}

		return $products;
	}