final protected function attributeCA($name, $label, $ordering = 1000) {
        $asId = df_eav_ca()->getDefaultAttributeSetId(); /** @var int $asId */
        $as = df_new_om(_AS::class); /** @var _AS $as */
		df_eav_setup()->addAttribute(IAddressMetadata::ENTITY_TYPE_ADDRESS, $name, [
			'input' => 'text'
			,'label' => $label
			,'position' => $ordering++
			,'required' => false
			,'sort_order' => $ordering
			,'system' => false
			/**
			 * 2019-03-06
			 * `varchar` (a solution without @see \Verdepieno\Core\Setup\UpgradeSchema )
			 * does not work for me.
			 * I guess it is a bug in the Magento 2 Community core.
			 */
			,'type' => 'static'
			,'visible' => true
		]);
		$a = df_eav_config()->getAttribute(IAddressMetadata::ENTITY_TYPE_ADDRESS, $name); /** @var A $a */
		$a->addData([
			IGroup::ATTRIBUTE_SET_ID => $asId
			,'attribute_group_id' => $as->getDefaultGroupId($asId)
			,'used_in_forms' => [
				'adminhtml_customer_address'
				,'customer_address_edit'
				,'customer_register_address'
				,'customer_address'
			]
		]);
		$a->save();
	}