title: Django: disable error messages for required field on initial form view?
body: <p>I've got a Django form that looks like this and allows users to make a choice:</p>
  
  <pre><code>class ChoiceForm(forms.Form):
      candidate = forms.CharField(widget=forms.HiddenInput)
      CHOICES = ((True, 'Yes',), (False, 'No',))
      choice_field = forms.ChoiceField(choices=CHOICES, required=True,
          widget=forms.RadioSelect)
  </code></pre>
  
  <p>The template looks like this:</p>
  
  <pre><code>    &lt;form id="pledge" action="/pledge" method="post"&gt;
          {% csrf_token %}
          {{ form.non_field_errors }}
          &lt;div class="fieldWrapper"&gt;
              {{ form.choice_field.errors }}
              {{ form.choice_field }}
          &lt;/div&gt;
          {{ form.candidate }}
          &lt;div class="form-actions"&gt;
              &lt;button type="submit" class="btn btn-primary" value="Submit"&gt;Submit your response&lt;/button&gt;
          &lt;/div&gt;
      &lt;/form&gt;
  </code></pre>
  
  <p>My view is like this:</p>
  
  <pre><code>def pledge(request, candidate_hashkey=None):
      candidate = None
      if request.method == 'POST':
          # process input
      else:
          candidate = get_object_or_404(Candidate, pledge_hashkey=candidate_hashkey)
          form = PledgeForm({'candidate': candidate_hashkey})
      context = {
          'form': form,
          'candidate': candidate
      }
      return render(request, 'frontend/pledge.html', context)
  </code></pre>
  
  <p>The problem is that on the initial GET view, before the user chooses anything, the form appears with an error at the top: "This value is required".</p>
  
  <p>How can I disable this for the initial view?</p>