title: argparse: extraneous arguments for argument with no stored value?
body: <p>Having a bit of problem with argparse in Python...</p>
  
  <pre><code>import argparse
  
  parser = argparse.ArgumentParser()
  parser.add_argument ("-o", "--optional", help="this is an optional argument")
  args = parser.parse_args()
  
  print ( args.optional )
  </code></pre>
  
  <p>Calling <code>test.py -h</code> will output...</p>
  
  <pre><code>usage: test.py [-h] [-o OPTIONAL]
  
  optional arguments:
    -h, --help            show this help message and exit
    -o OPTIONAL, --optional OPTIONAL
                          this is an optional argument
  </code></pre>
  
  <p>Is there any way I can get rid of the extra <code>OPTIONAL</code>s in the help menu? I know I could do this with <code>parser.add_argument ("-o", "--optional", help="this is an optional argument", action=store_true)</code>, except I can't because I need to call <code>args.optional</code> later on.</p>
  
  <p>Again, this isn't so much about the functionality of the program as the aesthetics because <code>test.py -o hello</code> would print <code>hello</code>.</p>