instance method render_collection

# File actionpack/lib/action_view/render/partials.rb, line 273
      def render_collection
        return nil if @collection.blank?

        if @options.key?(:spacer_template)
          spacer = find_template(@options[:spacer_template]).render(@view, @locals)
        end

        result = @template ? collection_with_template : collection_without_template
        result.join(spacer).html_safe
      end