ate name="__dynamicBackport">
  {{checkContext}}
  {{#if dataContextPresent}}
    {{# __dynamicWithDataContext}}{{> Template.contentBlock}}{{/__dynamicWithDataContext}}
  {{else}}
    {{! if there was no explicit 'data' argument, use the parent context}}
    {{# __dynamicWithDataContext template=template data=..}}{{> Template.contentBlock}}{{/__dynamicWithDataContext}}
  {{/if}}
</template>

<!-- Expects the data context to have a `template` property (the name of
the template to render) and a `data` propert