html! can't have classes, which isn't to spec

[krainboltgreene]

html! class: "no-js" do
  head do
    meta charset: "utf-8"
  end
end

ArgumentError: wrong number of arguments (1 for 0)
/Users/krainboltgreene/.rvm/gems/ruby-2.1.5@de-hackerlife/gems/paggio-0.2.4/lib/paggio/now.rb:17:in `html!'
views/index2.rb:1:in `<top (required)>'