title: argparse error with parsing required arguments
body: <p>I have a script saved as workspace.py</p>
  
  <pre><code>import argparse
  import os
  
  if __name__ == "__main__":
      parser = argparse.ArgumentParser()
      parser.add_argument('title', type=str, help="Will be displayed as the title")
      parser.add_argument('-f', '--folder', help='Point to the folder you want to read from (defaults to current folder in command prompt)', type=str, default=os.getcwd())
      args = parser.parse_args()
      print(args)
      someFunction(args.folder, args.title)
  </code></pre>
  
  <p>Which I call from terminal with:</p>
  
  <pre><code>workspace.py myTitle
  </code></pre>
  
  <p>Resulting in the error</p>
  
  <blockquote>
    <p>workspace.py: error: the following arguments are required: title</p>
  </blockquote>
  
  <p>I have no idea why this is happening because I supply "myTitle" in the terminal. If I specify a <code>default=</code> for the title argument it works perfectly with that value. The part that is throwing me is it doesn't even get to the <code>print(args)</code> so I cannot see what the program thinks is what, but instead fails at <code>args = parser.parse_args()</code></p>
  
  <p>I tried to even redo the exact example at: <a href="https://docs.python.org/2/howto/argparse.html#introducing-positional-arguments" rel="nofollow noreferrer">https://docs.python.org/2/howto/argparse.html#introducing-positional-arguments</a> (copied below)</p>
  
  <pre><code>import argparse
  parser = argparse.ArgumentParser()
  parser.add_argument("echo", help="echo the string you use here")
  args = parser.parse_args()
  print args.echo
  </code></pre>
  
  <p>Running</p>
  
  <pre><code>workspace.py hello
  </code></pre>
  
  <p>Results in (after adding parenthesis to the print for 3.X)</p>
  
  <blockquote>
    <p>workspace.py: error: the following arguments are required: echo</p>
  </blockquote>
  
  <p>Is there something I'm missing? Why does it not just print "hello"? Is there some Python 3 specific syntax I'm missing or something?</p>