code: def _init_fld2col_widths(self):
          
          # GO info namedtuple fields: NS dcnt level depth GO D1 name
          # GO header namedtuple fields: format_txt hdr_idx
          fld2col_widths = GoSubDagWr.fld2col_widths.copy()
          for fld, wid in self.oprtfmt.default_fld2col_widths.items():
              fld2col_widths[fld] = wid
          for fld in get_hdridx_flds():
              fld2col_widths[fld] = 2
          return fld2col_widths
docs: Return default column widths for writing an Excel Spreadsheet.