title: Python argparse fails when the script run without preceding py -2 or -3
body: <p>My python code is:</p>
  <pre><code># my_script.py
  
  import argparse
  parser = argparse.ArgumentParser()
  parser.add_argument(&quot;-v&quot;, &quot;--verbose&quot;, help=&quot;increase output verbosity&quot;,
                      action=&quot;store_true&quot;)
  args = parser.parse_args()
  if args.verbose:
      print(&quot;verbosity turned on&quot;)
  </code></pre>
  <p>My default python is <code>Python 3.7.4</code> (also python 2 is installed on my PC). When I run this script from Windows command line this way:</p>
  <pre><code>py -2 my_script.py
  </code></pre>
  <p>or this way:</p>
  <pre><code>py -3 my_script.py
  </code></pre>
  <p>The script works fine. But when I run this way:</p>
  <pre><code>my_script.py
  </code></pre>
  <p>I get the next error:</p>
  <pre><code>usage: my_script.py [-h] [-v]
  my_script.py: error: unrecognized arguments:
  </code></pre>
  <p>Why? I always run all my python scripts without preceding <code>py</code> and it works (they do not include <code>argparse</code> module)</p>
  <p>Can you please help - why python script that contains <code>arparse</code> does not run without preceding <code>py</code>?</p>