code: public byte[] getContents(FileColumn[] columns, List<String[]> lines)
          throws IOException
      {
          byte[] ret;
  
          // Excel spreadsheet
          if(format.isExcel())
          {
              ret = getExcelOutput(columns, lines);
          }
          else // Assume it's a CSV file
          {
              ret = getCSVOutput(lines);
          }
  
          return ret;
      }
docs: Returns the formatted output file contents.
  @param columns The column definitions for the output file
  @param lines The lines to add to the output file
  @return The formatted output file contents
  @throws IOException if the file cannot be opened