title: "pass" same as "return None" in Python?
body: <p>I have been learning python about a week now, below is the question:</p>
  
  <p><strong>Code</strong></p>
  
  <pre><code>def Foo():
      pass
  
  def Bar():
      return None
  </code></pre>
  
  <p><strong>Usage</strong></p>
  
  <pre><code>a = Foo()
  print(a)
  # None
  b = Bar()
  print(b)
  # None
  </code></pre>
  
  <p><strong>Question</strong>:
  1. Why do we need <em>pass</em> when we already have <em>return None</em>? Is there some scenario that <em>return None</em> can not handle but <em>pass</em> can?</p>