title: SystemExit: 2 error when calling parse_args() within ipython
body: <p>I'm learning basics of Python and got already stuck at the beginning of argparse tutorial.  I'm getting the following error:</p>
  <pre class="lang-py prettyprint-override"><code>import argparse
  parser = argparse.ArgumentParser()
  args = parser.parse_args()
  </code></pre>
  <pre class="lang-none prettyprint-override"><code>usage: __main__.py [-h] echo
  __main__.py: error: unrecognized arguments: -f
  An exception has occurred, use %tb to see the full traceback.
  
  SystemExit: 2
  </code></pre>
  <p>a %tb command gives the following output:</p>
  <pre class="lang-none prettyprint-override"><code>SystemExit                                Traceback (most recent call last)
  &lt;ipython-input-16-843cc484f12f&gt; in &lt;module&gt;()
  ----&gt; 1 args = parser.parse_args()
  
  C:\Users\Haik\Anaconda2\lib\argparse.pyc in parse_args(self, args, namespace)
     1702         if argv:
     1703             msg = _('unrecognized arguments: %s')
  -&gt; 1704             self.error(msg % ' '.join(argv))
     1705         return args
     1706 
  
  C:\Users\Haik\Anaconda2\lib\argparse.pyc in error(self, message)
     2372         &quot;&quot;&quot;
     2373         self.print_usage(_sys.stderr)
  -&gt; 2374         self.exit(2, _('%s: error: %s\n') % (self.prog, message))
  
  C:\Users\Haik\Anaconda2\lib\argparse.pyc in exit(self, status, message)
     2360         if message:
     2361             self._print_message(message, _sys.stderr)
  -&gt; 2362         _sys.exit(status)
     2363 
     2364     def error(self, message):
  
  SystemExit: 2
  </code></pre>
  <p>How could I fix this problem?</p>