Merging cells with Ruby Gem Spreadsheet

How do I merge cells using the Ruby Spreadsheet gem. I would like to merge the first 6 cells on the first row of a worksheet. When I try the following it does not work: merge_format = Spreadsheet::Format.new :align => :merge 6.times do |j| sheet.row(0).set_format(j,merge_format) end What am I doing wrong?

[watanata2000]

spreadsheet セル結合

[gamaguchi]

Ruby Spreadsheet，ちょっと気になってみたので調べてみたら罫線は使えるようだけどセルの結合ができないっぽいのでBiweekly Reportの再現は無理，と思ったら一応非公開APIで結合の実装自体は行われているようだ．