/// <summary> A factory method which takes in an excel file and reads in the contents.
///
/// </summary>
/// <exception cref=""> IOException
/// </exception>
/// <exception cref=""> BiffException
/// </exception>
/// <param name="is">an open stream which is the the excel 97 spreadsheet to parse
/// </param>
/// <param name="ws">the settings for the workbook
/// </param>
/// <returns> a workbook instance
/// </returns>
public static Workbook getWorkbook(Stream stream, WorkbookSettings ws)
{
NExcel.Read.Biff.File dataFile = new NExcel.Read.Biff.File(stream, ws);
Workbook workbook = new WorkbookParser(dataFile, ws);
workbook.parse();
return(workbook);
}