code: def tag_for_collapsible_row(obj, params)
        _html = ""
        if obj && obj.respond_to?(:parent) && obj.parent
          _html << %{<tr class="#{obj.class.name.downcase}_#{obj.parent.id} #{params[:class]}" style="display: none; #{params[:style]}">}
        else
          _html << %{<tr class="#{params[:class]}" style="#{params[:style]}">}
        end
        _html
      end
docs: ================================================================================================