render

# File actionview/lib/action_view/helpers/tags/grouped_collection_select.rb, line 21
        def render
          option_tags_options = {
            selected: @options.fetch(:selected) { value },
            disabled: @options[:disabled]
          }

          select_content_tag(
            option_groups_from_collection_for_select(@collection, @group_method, @group_label_method, @option_key_method, @option_value_method, option_tags_options), @options, @html_options
          )
        end