title: Meteor : get the opposite statement from a variable into handlebars
body: <p>I'm discovering Meteor and was asking myself for a thing.
  How in a template can we reverse the boolean into the handlebars from a template ?</p>
  
  <p>There is an example of what I'm trying to do :</p>
  
  <p><strong>task.html</strong></p>
  
  <pre><code>&lt;li class="{{#if !checked}}checked{{/if}}"&gt;
      ...
  </code></pre>
  
  <p>But I'm getting an error "Expected close "}}". Maybe it's not possible.</p>
  
  <p>Thank you !</p>