title: What is the equivalent of a Swift completion block in Python?
body: <p>In Swift we can write a function with a completion block like this:</p>
  
  <pre><code>func thisNeedsToFinishBeforeWeCanDoTheNextStep(completion: () -&gt; ()) {
      print("The quick brown fox")
      completion()
  }
  </code></pre>
  
  <p>And then when we call it, we can put something inside of that block to execute once it's finished it's process:</p>
  
  <pre><code>func thisFunctionNeedsToExecuteSecond() {
     print("jumped over the lazy dog")
  }
  </code></pre>
  
  <p>What is the equivalent in Python?</p>