Opens an existing Excel spreadsheet.
The path and name of the file to open. The path can be relative or absolute. The file must be a OOXML format (Excel 2007 or later) .xlsx file or BIFF8 format (Excel 97 or later) .xls file.
object representing the file opened.
If the file cannot be found or opened, or if ExcelWriter cannot parse the file as a OOXML or BIFF8 file.
ExcelWriter supports Excel's OOXML (Excel 2007 or later) and BIFF8 (Excel 97 or later) format only. Do not use this method to open BIFF7 (Excel 95) files.