/**
  * Shipping mode: 'both', 'including', 'excluding'
  *
  * @return string
  */
 public function getDisplayShippingMode()
 {
     if ($this->taxConfig->displayCartShippingBoth()) {
         return 'both';
     }
     if ($this->taxConfig->displayCartShippingExclTax()) {
         return 'excluding';
     }
     return 'including';
 }