An exception which is thrown when the Persistence device fails
because the file path is not valid, the data to print is null or contain nulls, or
there was an error writing on the output file.
An exception which is thrown when the Printer device fails
because the file path is not valid, the data to print is null or contain nulls, or
there was an error writing on the output file.
Method that prints the contents of the shopping cart
This method is called internally for the GUI class and does not
correspond to any external GUI action