ies.
These are property names in the Backbone model.
This can also be a single string in the case of 
having only one dependency property.</p>
</li>
<li><p><code>fn</code> The callback function that will be invoked with
current values for each dependency property as arguments
in the order specified by <code>dependencies</code>.
This function will be invoked:</p>
<ul>
<li><p>once immediately after calling <code>wire</code></p>
</li>
<li><p>every time any dependency property changes</p>
</li>
</ul>
<p><code>f