public function getBindingId($orderIndex = 0)
    {
        $bindingInfo = $this->getBindingInfo($orderIndex);
        return array_key_exists('bindingId', $bindingInfo) ? $bindingInfo['bindingId'] : null;
    }
public function getBindingId($orderIndex = 0)
    {
        $bindingInfo = $this->getBindingInfo($orderIndex);
        return array_key_exists('bindingId', $bindingInfo) ? $bindingInfo['bindingId'] : null;
    }
public function getBindingId ( $ orderIndex = 0 ) { $ bindingInfo = $ this -> getBindingInfo ( $ orderIndex ) ; return array_key_exists ( 'bindingId' , $ bindingInfo ) ? $ bindingInfo [ 'bindingId' ] : null ; }
The identifier of the bundle used for payment.

@param int $orderIndex
@return mixed|null
The identifier of the bundle used for payment .