```ruby
module NivoHelper
  def slider(files, hash = {})
    options = { :theme => :default }
    options.merge!(hash)

    content_tag(:div, :class => "slider-wrapper theme-#{options[:theme]}") do
      content_tag(:div, :class => "nivoSlider #{options[:class]}", :id => "#{options[:id]}") do
        content = ""

        files.each do |file|
          if file.kind_of?(String)
            content += image_tag file, :data => { :thumb => file }
          elsif file.kind_of?(Array)
            content += image_tag file[0], :data => { :thumb => file[0] },
                                          :title => file[1]
          end
        end

        content
      end
    end

  end
end```

Change the syntax of the nivo_slider helper
user
```ruby
module NivoHelper
  def nivo_slider(hash = {}, &block)
    options = { :theme => :default, :id => "slider" }
    options.merge!(hash)
    klass = "slide-wrapper theme-#{options[:theme]}"
    id = options[:id]

    content_tag(:div, :id => id, :class => klass) do
      content_tag(:div, :class => "nivoSlider #{options[:class]}") do
        yield
      end
    end

  end
end```
assistant