def from_excel path, opts={}
        opts = {
          worksheet_id: 0,
          row_id: 0
        }.merge opts

        worksheet, headers = read_from_excel(path, opts)
        df = Daru::DataFrame.new({})
        headers.each_with_index do |h,i|
          col = worksheet.column(i).to_a
          col.delete_at 0
          df[h] = col
        end

        df
      end
Functions for loading/writing Excel files.