title: Multiple options for the same argument in ArgumentParser Python
body: <p>I was wondering if it is possible to give multiple options for the same arguments in ArgumentParser.</p>
  
  <p>I am aware that it is possible to do it by giving "-" in addition to "--" for the same argument. For example:</p>
  
  <pre><code>parser.add_argument('-d', '--dataset_name', type=str)
  </code></pre>
  
  <p>The previous code is legit. However, I was wondering if the following code is still valid?</p>
  
  <pre><code>parser.add_argument('--dn', '--dataset_name', type=str)
  </code></pre>
  
  <p>Now I have specified two arg options with "--" for the same argument.</p>
  
  <p>Another question I have is that if the following code is correct?</p>
  
  <pre><code>parser.add_argument('-dn', '--dataset_name', type=str)
  </code></pre>
  
  <p>Here I am giving two character for the option defined with "-".</p>