title: Parsing only optional arguments with argparse
body: <p>I'm running into an issue with argparse's optional arguments. I want to be able to set integer parameters on command line along with true/false flags like so</p>
  
  <pre><code>python3 create.py k=7 split=9
  </code></pre>
  
  <p>My issue is that argparse ignores the equals and takes these arguments as [k=7,split=9].  As you can see, they end up being strings rather than the integers I want. How can I specify on the command line what arguments I want to be what integer?</p>
  
  <p>For the record this is what my code looks like</p>
  
  <pre><code>parser = argparse.ArgumentParser()
  parser.add_argument('k', nargs='?', default=6)
  parser.add_argument('split', nargs='?', default=0.67)
  arg = parser.parse_args()
  </code></pre>