class Sass::Selector::Sequence

def group_selectors(seq)
  newseq = []
  tail = seq.dup
  until tail.empty?
    head = []
    begin
      head << tail.shift
    end while !tail.empty? && head.last.is_a?(String) || tail.first.is_a?(String)
    newseq << head
  end
  newseq
end