Helper/Data.php
public function getSubscriberAddressBook($website)
    {
        $website = $this->storeManager->getWebsite($website);

        return $this->scopeConfig->getValue(
            \Dotdigitalgroup\Email\Helper\Config::XML_PATH_CONNECTOR_SUBSCRIBERS_ADDRESS_BOOK_ID,
            \Magento\Store\Model\ScopeInterface::SCOPE_WEBSITE,
            $website->getId()
        );
    }
public function getSubscriberAddressBook($website)
    {
        $website = $this->storeManager->getWebsite($website);

        return $this->scopeConfig->getValue(
            \Dotdigitalgroup\Email\Helper\Config::XML_PATH_CONNECTOR_SUBSCRIBERS_ADDRESS_BOOK_ID,
            \Magento\Store\Model\ScopeInterface::SCOPE_WEBSITE,
            $website->getId()
        );
    }
public function getSubscriberAddressBook ( $ website ) { $ website = $ this -> storeManager -> getWebsite ( $ website ) ; return $ this -> scopeConfig -> getValue ( \ Dotdigitalgroup \ Email \ Helper \ Config :: XML_PATH_CONNECTOR_SUBSCRIBERS_ADDRESS_BOOK_ID , \ Magento \ Store \ Model \ ScopeInterface :: SCOPE_WEBSITE , $ website -> getId ( ) ) ; }
Subscriber address book.

@param \Magento\Store\Api\Data\WebsiteInterface|int $website

@return string|boolean
Subscriber address book .