title: Argparse with multiple subparsers in one command
body: <p>I want to be able to achieve something like this:</p>
  
  <p>'python program host add 192.168.1.1'</p>
  
  <p>'python program host remove 192.168.1.1'</p>
  
  <p>I don't know how to properly code 'add' or 'remove' subparser.</p>
  
  <pre><code>import argparse
  
  parser = argparse.ArgumentParser()
  subparsers = parser.add_subparsers()
  
  host_cmd = subparsers.add_parser('host')
  host_cmd.set_defaults(func=host)
  add_cmd.add_argument('add', dest='add')
  </code></pre>
  
  <p>I want to be able to read the variable that the user pass in (in this case, 192.168.1.1).</p>