class ActionView::PartialRenderer

def render_collection
  return nil if @collection.blank?
  if @options.key?(:spacer_template)
    spacer = find_template(@options[:spacer_template], @locals.keys).render(@view, @locals)
  end
  result = @template ? collection_with_template : collection_without_template
  result.join(spacer).html_safe
end