title: Enter a valid date/time for DatetimeInput on Django Form
body: <p>I populate the fields for editing an event. The fields are shown as "DD/MM/YY HH:MM:SS", but when I change any of the values - although preserving the format - and try to save it, it shows the error: </p>
  
  <blockquote>
    <p>Enter a valid date/time</p>
  </blockquote>
  
  <pre><code>class EventForm(forms.ModelForm):
      ...
      date = forms.DateTimeField(widget=forms.widgets.DateTimeInput(format="%d/%m/%Y %H:%M:%S", attrs={'placeholder':"DD/MM/YY HH:MM:SS"}))
      ...
  
  class Meta:
      model = Event
  </code></pre>
  
  <p>views.py</p>
  
  <pre><code>def event(request, category_slug, event_slug):
      ...
      event = Event.objects.get(slug=event_slug)
      form = EventForm(instance=my_event)
      context_dict["edit_event_form"] = form
      ...
  
  return render(request, 'handsup/event.html', context=context_dict)
  </code></pre>
  
  <p>This is how the field is called in event.html:          </p>
  
  <pre><code> &lt;div class="form-group"&gt;
       {{ edit_event_form.date.errors }}
       {{ edit_event_form.date.label_tag }}
       {{ edit_event_form.date|addclass:"form-control form-style"}}
  &lt;/div&gt;
  </code></pre>
  
  <p>Any comment or suggestion is greatly appreciated. Thank you.</p>