<div class="actions">
  <div class="content">
    {{#if template}}
      {{yield}}
    {{else}}
      <ul class="navigation-actions">
        <li>
          <button
            disabled={{disablePrevious}}
            class="previous"
            {{action "previous" target=parentView.parentView}}></button>
        </li>

        <li>
          <button
            disabled={{disableNext}}
            class="next"
            {{action "next" target=parentView.parentView}}></button>
        </li>
      </ul>
    {{/if}}
  </div>

  <div class="close">
    <button {{action "close" target=parentView.parentView}}></button>
  </div>
</div>

<div class="actions">
  <div class="content">
    {{#if hasBlock}}
      {{yield}}
    {{else}}
      <ul class="navigation-actions">
        <li>
          <button
            disabled={{disablePrevious}}
            class="previous"
            {{action "previous" target=parentView.parentView}}></button>
        </li>

        <li>
          <button
            disabled={{disableNext}}
            class="next"
            {{action "next" target=parentView.parentView}}></button>
        </li>
      </ul>
    {{/if}}
  </div>

  <div class="close">
    <button {{action "close" target=parentView.parentView}}></button>
  </div>
</div>

Use hasBlock instead of accessing private variable
Use hasBlock instead of accessing private variable
