Ember: Add attribute to element generated by helper

I have the following template file:

<h2 style="margin-top: 20px" class="ui header"></h2>
<div id="sessions-list">
  
    
      <div class="unscheduled" data-toggle="tooltip" data-animation="false" data-placement="top" draggable="true">
        <span class="text">
           | 
        </span>
        
          <span class="text speaker">
            
          </span>
        
      </div>
    
  
</div>

I want to add a data attribute to the elements generated by the helper. This attribute should essentially have its value as session, and it's not the same as content. Any idea how to accomplish this?