title: Django icalendar dtstart datetime issue
body: <p>I have a form in Django-python for an event program. I'm trying to create an ics file for the events with icalendar, for this, I want to get the values 'dtstart' and 'dtend' from the variables 'starttime' and 'endtime' in the form, but I'm getting the code: Wrong datetime format. Anyone with any advice to solve this issue?</p>
  <p>ERROR</p>
  <pre><code>            elif not ical[15:]:
                  return datetime(*timetuple)
              elif ical[15:16] == 'Z':
                  return pytz.utc.localize(datetime(*timetuple))
              else:
                  raise ValueError(ical)
          except:
              raise ValueError('Wrong datetime format: %s' % ical) …
  class vDuration(object):
      &quot;&quot;&quot;Subclass of timedelta that renders itself in the iCalendar DURATION
      format.
      &quot;&quot;&quot;
  </code></pre>
  <p>CODE</p>
  <pre><code>def event(request, id=None):
      instance = Event_cal()
      
      if id:
          instance = get_object_or_404(Event_cal, pk=id)
      else:
          instance = Event_cal()
  
      form = EventForm(request.POST or None, instance=instance)
      if request.POST and form.is_valid():
          form.save()
          
          startdate = request.POST.get('starttime')
          endate = request.POST.get('endtime')
  
          event = Event()
          event.add('summary', 'My Summary')
          event.add('dtstart', vDatetime.from_ical(startdate))
          event.add('dtend', vDatetime.from_ical(endate))
  </code></pre>
  <p>Thanks in advance, I am learning python, so I don't have have much experience.</p>