title: ipykernel_launcher.py: error: the following arguments are required: -m/--mode
body: <p>I have a long code and I keep getting this error when I run it. does anyone know what is this error about?</p>
  <p>`    usage: ipykernel_launcher.py [-h] -m MODE</p>
  <pre><code>ipykernel_launcher.py: error: the following arguments are required: -m/--mode
  
  An exception has occurred, use %tb to see the full traceback.
   
  SystemExit: 2`
  </code></pre>