title: Check if PHP function returns null or nothing
body: <p>I have this code</p>
  
  <pre><code> $return = $ep-&gt;$method($params);
   if ($return === null) {
    throw new Exception('Endpoint has no return value');
   }
   return $return;
  </code></pre>
  
  <p>Is there any way to distinguish between a method that returns <code>null</code> and a method that does not return anything?</p>