public function add_shipping_method( $type ) {
		if ( null === $this->get_id() ) {
			$this->save();
		}

		$instance_id     = 0;
		$wc_shipping     = WC_Shipping::instance();
		$allowed_classes = $wc_shipping->get_shipping_method_class_names();
		$count           = $this->data_store->get_method_count( $this->get_id() );

		if ( in_array( $type, array_keys( $allowed_classes ), true ) ) {
			$instance_id = $this->data_store->add_method( $this->get_id(), $type, $count + 1 );
		}

		if ( $instance_id ) {
			do_action( 'woocommerce_shipping_zone_method_added', $instance_id, $type, $this->get_id() );
		}

		WC_Cache_Helper::get_transient_version( 'shipping', true );

		return $instance_id;
	}