title: Error "An exception has occurred, use %tb to see the full traceback"
body: <pre><code>#!/usr/bin/env python
  import os, random, argparse
  from PIL import Image
  import numpy as np
  </code></pre>
  <p>Getting an error when running the below code</p>
  <pre><code>parser = argparse.ArgumentParser(description='Creates a photomosaic from input images')
  parser.add_argument('--target', dest='target', required=True, help=&quot;Image to create mosaic from&quot;)
  parser.add_argument('--images', dest='images', required=True, help=&quot;Diectory of images&quot;)
  parser.add_argument('--grid', nargs=2, dest='grid', required=True, help=&quot;Size of photo mosaic&quot;)
  parser.add_argument('--output', dest='output', required=False)
  
  args = parser.parse_args()
  </code></pre>
  <p>Error</p>
  <pre><code>usage: ipykernel_launcher.py [-h] --target TARGET --images IMAGES --grid GRID
                               GRID [--output OUTPUT]
  ipykernel_launcher.py: error: the following arguments are required: --target, --images, --grid
  An exception has occurred, use %tb to see the full traceback.
  
  SystemExit: 2
  </code></pre>
  <p>Please let me what change to be made to the above code.</p>
  <p>I read that exit should not be made, however, I haven't used that in my code anywhere</p>