title: What is the datetime format for flask-restful parser?
body: <p>Let's say that I have following parser inside my get method:</p>
  
  <pre><code>from flask.ext.restful import reqparse
  
  parser = reqparse.RequestParser()
  parser.add_argument('when', type=datetime, help='Input wasn\'t valid!')
  </code></pre>
  
  <p>And then I want to test the said get method with curl...</p>
  
  <pre><code>curl --data "when=[WHAT SHOULD I WRITE HERE?]" localhost:5000/myGet
  </code></pre>
  
  <p>So the question is, how I should call the get method? I've tried numerous different formats, tried to read rfc228 standard, etc. but I can't figure out the right format.</p>