title: Difference between return None and pass
body: <p>consider my scenario, I have a method which is kind of a factory that returns me the action based on the status that I pass.</p>
  
  <pre><code>def factory(status):
      action = {
          1: action_1,
          2: action_2,
          3: action_3,
      }.get(status)
  
      return action
  </code></pre>
  
  <p>and these are the actions,</p>
  
  <pre><code>def action_1():
      # making db call
      action_1_db_call()
  
  def action_2():
      # making db call
      action_2_db_call()
  
  def action_3():
      # It will do nothing
      pass
  </code></pre>
  
  <p>I will basically do the following in the main code,</p>
  
  <pre><code>action = factory(1)
  action()
  </code></pre>
  
  <p>So here, which is the right approach for action_3? Can I just use <code>pass</code> for this method or I should return <code>None</code>. which one is advisable and a good practice?</p>