title: Liquidsoap Icecast request.dynamic error
body: <p>I would like to create dynamic playlist with liquidesoap and icecast. I've just copied the tutorial from the liquidsoap website but unfortunately it does not work.</p>
  
  <p>This is my code:</p>
  
  <pre><code>def get_next() =
    result = list.hd(get_process_lines("/var/www/radiod/yii program-generator/next-track 1"))
  
    # Create and return a request using this result
    request.create(result)
  end
  
  # Create the source
  s = request.dynamic(id="s", get_next)
  
  # Output
  source = output.icecast(%mp3, host="localhost", port=8000, mount="opera.mp3", password="asd123", s)
  </code></pre>
  
  <p>I get this error message when I run the check command:</p>
  
  <pre><code>Invalid value at line 9, char 20-37: That source is fallible.
  </code></pre>
  
  <p>So, the problem will be around this line:</p>
  
  <pre><code>s = request.dynamic(id="s", get_next)
  </code></pre>
  
  <p>Can you help me what could be the failure?</p>
  
  <p>Thanking you in advance!</p>