title: freemarker templates check if sequence is empty
body: <p>I would like to check if a sequence is empty in a freemarker template.</p>
  
  <p>This snippet works to check if a sequence <strong><em>contains</em></strong> a value:</p>
  
  <pre><code>&lt;#if node.attachments?seq_contains("blue")&gt;
    &lt;pre&gt;hello&lt;/pre&gt;
  &lt;/#if&gt;
  </code></pre>
  
  <p>However, if <code>node.attachments</code> is empty i would like to do something else.</p>
  
  <p>That is the syntax for this?</p>