title: Argparse with spaces
body: <p>I have the following script:</p>
  
  <pre><code>import argparse
  parser = argparse.ArgumentParser()
  parser.add_argument('--arg1',  dest='arg1')
  parse_results = parser.parse_known_args(['--arg1 = value'])
  </code></pre>
  
  <p>However I get the result:</p>
  
  <pre><code>(Namespace(arg1=None), ['--arg1 = value'])
  </code></pre>
  
  <p>Is there a way using argparse to accept this kind of input where there are spaces between argument, = and the value? </p>