class Sass::Selector::Sequence

def extended_not_expanded_to_s(extended_not_expanded)
  extended_not_expanded.map do |choices|
    choices = choices.map do |sel|
      next sel.first.to_s if sel.size == 1
      "#{sel.join ' '}"
    end
    next choices.first if choices.size == 1 && !choices.include?(' ')
    "(#{choices.join ', '})"
  end.join ' '
end