See attributes from parent class: Data::TableReader::Decoder.
workbook
This is an instance of Spreadsheet::ParseExcel, Spreadsheet::ParseXLSX, or Spreadsheet::XLSX (which all
happen to have the same API). Subclasses can lazy-build this from the "file_handle".
sheet
This is either a sheet name, a regex for matching a sheet name, or a parser's worksheet object. It is
also optional; if not set, all sheets will be iterated.
xls_formatter
An optional object that is passed to Excel parsers Spreadsheet::ParseXLSX and Spreadsheet::ParseExcel. It
governs how raw data in cells is formatted into values depending on the type of the cell. The parsers
create one of their own if none is provided, usually Spreadsheet::ParseExcel::FmtDefault.
Note that it does not work for Spreadsheet::XLSX, which hardcodes the formatter as
Spreadsheet::XLSX::Fmt2007.