public function beforeDeleteById(
        \Magento\Customer\Api\CustomerRepositoryInterface $subject,
        $customerId
    ) {
        $this->deleteSnaps($customerId);
        $this->deleteChange($customerId);
        $result = [$customerId];
        return $result;
    }
public function beforeDeleteById(
        \Magento\Customer\Api\CustomerRepositoryInterface $subject,
        $customerId
    ) {
        $this->deleteSnaps($customerId);
        $this->deleteChange($customerId);
        $result = [$customerId];
        return $result;
    }
public function beforeDeleteById ( \ Magento \ Customer \ Api \ CustomerRepositoryInterface $ subject , $ customerId ) { $ this -> deleteSnaps ( $ customerId ) ; $ this -> deleteChange ( $ customerId ) ; $ result = [ $ customerId ] ; return $ result ; }
Remove customer related data from Downline on customer delete from adminhtml.

@param \Magento\Customer\Api\CustomerRepositoryInterface $subject
@param $customerId
@return array
Remove customer related data from Downline on customer delete from adminhtml .