class Sass::Selector::Pseudo

def unify(sels)

Other tags:
    See: SimpleSequence#unify -
def unify(sels)
  return if type == :element && sels.any? do |sel|
    sel.is_a?(Pseudo) && sel.type == :element &&
      (sel.name != name || sel.arg != arg || sel.selector != selector)
  end
  super
end