title: Argparse - Custom Action With No Argument?
body: <pre><code>class StartAction(argparse.Action):
      def __call__(self, parser, namespace, values, option_string=None):
          print &quot;Hello&quot;
  
  start.add_argument('-s', '--start', action=StartAction)
  </code></pre>
  <p>I know normally having the action be something like 'store_true' would prevent the requirement of an argument, but is there a way to use a custom action and still not require an argument to be passed?</p>
  <p>So what I want is:</p>
  <blockquote>
  <p>python example.py -s</p>
  <p>Hello</p>
  </blockquote>