vis = xlsx.GetSheetVisibility(id[, sheet])
sheet parameter.
The return value will be one of the following special constants:
#XLSX_VISIBILITY_VISIBLE
#XLSX_VISIBILITY_HIDDEN
#XLSX_VISIBILITY_VERYHIDDEN
The sheet parameter is optional. If it is omitted, the worksheet set by xlsx.SetDefaultSheet()
will be used. Sheet indices start at 1 for the first worksheet.