code: function writeCols(ws, cols, contents) {
          let range = ws['!ref'];
          range = check.undefined(range) ? 'A1:A1' : range;
          let dRange = xlsx.utils.decode_range(range);
          let newRef = {s: {c: 0, r: 0}, e: {c: dRange.e.c, r: dRange.e.r}};
          let encCell;
          if (typeof cols === 'string') {
              cols = cols.split(',');
          }
          for (let i = 0; i < cols.length; ++i) {
              let dCol = xlsx.utils.decode_col(cols[i]);
              let cellVal = contents[i];
              if (dCol > newRef.e.c) {
                  newRef.e.c = dCol;
              }
  
  
              for (let R = dRange.s.r; R < cellVal.length; ++R) {
                  encCell = xlsx.utils.encode_cell({c: dCol, r: R});
                  if (R > newRef.e.r) {
                      newRef.e.r = R;
                  }
  
                  ws[encCell] = updateCellData(ws[encCell], cellVal[R]);
              }
          }
          ws['!ref'] = xlsx.utils.encode_range(newRef);
          return ws;
      }
docs: writes specified cols to an opened workbook
  @function
  @param {object} ws - worksheet.
  @param {object} cols - cols where contents are written
  @param {boolean} contents - contents that are to written to specified cols
  @return {object} ws - returns the modified worksheet