code: public ReceiptTemplateBuilder setSummary(BigDecimal subtotal,
  			BigDecimal shippingCost, BigDecimal totalTax, BigDecimal totalCost) {
  		Summary summary = new Summary(subtotal, shippingCost, totalTax,
  				totalCost);
  		return this.setSummary(summary);
  	}
docs: Sets the payment {@link Summary}. This field is required and can't be
  null. These numbers should be valid and well formatted decimal numbers,
  using '.' (dot) as the decimal separator. Note that most currencies only
  accept up to 2 decimal places.
  
  @param subtotal
  the subtotal.
  @param shippingCost
  the cost of the shipping.
  @param totalTax
  the total tax.
  @param totalCost
  the total cost.
  @return this builder.