class Nokogiri::XML::NodeSet

def remove_class name = nil
  each do |el|
    next unless el.respond_to? :get_attribute
    if name
      classes = el.get_attribute('class').to_s.split(" ")
      el.set_attribute('class', (classes - [name]).uniq.join(" "))
    else
      el.remove_attribute("class")
    end
  end
  self
end