code: public PassengerSegmentInfoBuilder addProductInfo(String title, String value) {
  		ProductInfo productInfo = new ProductInfo(title, value);
  		segmentInfo.addProductInfo(productInfo);
  		return this;
  	}
docs: Adds a {@link ProductInfo} object to the list of products the passenger
  purchased in the current {@link PassengerSegmentInfo}. This field is
  mandatory and there must be at least one element.
  
  @param title
  the product title. It can't be empty.
  @param value
  the product description. It can't be empty.
  @return this builder.