title: How to check if an array is in a list of arrays in Python?
body: <p>I have a list of 3x3 arrays <code>l</code> and I want to check if a different single 3x3 array <code>a</code> is in the list. I tried like this:</p>
  
  <pre><code>a in l
  </code></pre>
  
  <p>but it couldn't be executed beacuse of the following error:</p>
  
  <pre><code>ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()
  </code></pre>
  
  <p>I cannot grasp why such a comparison would be ambiguous (the intention is clear), but anyway, is there a way to solve my problem?</p>