
Extract the relevant logic from `formula.rb`, moving to `keg.rb` and then use this logic in `bundle/commands/cleanup.rb` to ensure that we don't say we need to uninstall formulae that should be still kept.
Extract the relevant logic from `formula.rb`, moving to `keg.rb` and then use this logic in `bundle/commands/cleanup.rb` to ensure that we don't say we need to uninstall formulae that should be still kept.