!!!XML
%storage_volumes
  - @elements.each do |volume|
    %storage_volume{ :href => storage_volume_url(volume.id), :id => volume.id }
      %created<
        =volume.created
      %capacity<
        =volume.capacity
      - unless volume.device.nil?
        %device<
          =volume.device
      - unless volume.instance_id.nil?
        %instance{:href => instance_url(volume.instance_id), :id => volume.instance_id}