title: The time data does not match format
body: <p>Hello I am trying to convert a string which is <code>a = "2019-04-22 00:00"</code> to a datetime but it does not work, I tried this : </p>
  
  <pre><code>a = datetime.datetime.strptime(a, '%Y-%m-%d %H:%M')
  </code></pre>
  
  <p>But I got </p>
  
  <blockquote>
    <p>time data 'start_period' does not match format '%Y-%m-%d %H:%M'</p>
  </blockquote>
  
  <p>I precise <code>start_period</code> is get by this : <code>a = request.POST.get('start_period')</code></p>