title: One liner Python equivalent of JavaScript like assignment when value is falsey
body: <p>Consider a function in JavaScript:<br>
  If <code>val</code> is not defined in the first call, it becomes <code>0</code>  </p>
  
  <pre><code>function someRecursiveFn (item, val) {
      val = val || 0;
      ...
  }
  </code></pre>
  
  <p>How do I assign the same way in Python?</p>
  
  <pre><code>def someRecursiveFn(item, val):
      val = ??
      ...
  </code></pre>