title: How to specify a minimum or maximum float value with argparse
body: <p>How can I specify a minimum or maximum floating point argument using <code>argprase</code>? I'd like to be able to provide a command-line argument between a min and max floating point value.</p>
  
  <p>The closest thing I can find is the <code>choices</code> option in <code>add_argument()</code>, but that only specifies allowable values for the argument.</p>
  
  <pre><code>parser.add_argument("L", type=float, choices=range(2))
  </code></pre>
  
  <p>The command-line argument <code>0.5</code> for L fails:</p>
  
  <pre><code>invalid choice: 0.5 (choose from 0, 1)
  </code></pre>