title: python using argparse.ArgumentParser method
body: <p>I've tried to learn how <code>argparse.ArgumentParser</code> works and I've write a couple lines for that : </p>
  
  <pre><code>global firstProduct
  global secondProduct 
  myparser=argparse.ArgumentParser(description='parser test')
  myparser.add_argument("product1",help="enter product1",dest='product_1')
  myparser.add_argument("product2",help="enter product2",dest='product_2')
  
  args=myparser.parse_args()
  
  firstProduct=args.product_1
  secondProduct=args.product_2
  </code></pre>
  
  <p>I just want to that when User run this script with 2 parameters  my code assign them to <code>firstProduct</code> and <code>secondProduct</code> respectively. However it doesn’t work. Is there anyone to tell me why? thanks in advance</p>