title: How to open file using argparse?
body: <p>I want to open file for reading using argparse.
  In cmd it must look like: my_program.py /filepath</p>
  
  <p>That's my try:</p>
  
  <pre><code>parser = argparse.ArgumentParser()
  parser.add_argument('file', type = file)
  args = parser.parse_args()
  </code></pre>