title: How to create a specific default list in defaultdict?
body: <p>I am trying to build a defaultdict which is initialized with a specific list. Such that if I access the dict using a key that does exist, it will be initialized with a specific list, let's say <code>[True, True, True]</code>.</p>
  
  <p>Instead of doing this</p>
  
  <pre><code>my_defaultdict = collections.defaultdict(list)
  </code></pre>
  
  <p>So, for example, something like this (obviously would not work)</p>
  
  <pre><code>my_defaultdict = collections.defaultdict([True, True, True])
  </code></pre>
  
  <p>I tried something like this, but this does not work</p>
  
  <pre><code>my_defaultdict = collections.defaultdict(lambda: list[True, True, True])
  </code></pre>
  
  <p>I looked in <a href="https://stackoverflow.com/questions/8419401/python-defaultdict-and-lambda">this question</a> for a start, but could not figure it out.</p>