pi.emberjs.com/classes/Ember.Helper.html"><code>Ember.Helper</code></a>. Helper classes must contain a
<a href="https://api.emberjs.com/classes/Ember.Helper.html#method_compute"><code>compute</code></a> method that behaves the same as the function passed to
<a href="https://api.emberjs.com/classes/Ember.Helper.html#method_helper"><code>Ember.Helper.helper</code></a>.  In order to access a service, you must first inject it
into the class-based helper.  Once added, you can call the service's methods or
access