code: def render_layout(self, form, context, template_pack=TEMPLATE_PACK):
          
          # Writing the label values into the field placeholders.
          # This is done at rendering time, so the Form.__init__() could update any labels before.
          # Django 1.11 no longer lets EmailInput or URLInput inherit from TextInput,
          # so checking for `Input` instead while excluding `HiddenInput`.
          for field in form.fields.values():
              if field.label and \
                      isinstance(field.widget, (Input, forms.Textarea)) and \
                      not isinstance(field.widget, forms.HiddenInput):
                  field.widget.attrs['placeholder'] = u"{0}:".format(field.label)
  
          return super(CompactLabelsCommentFormHelper, self).render_layout(form, context, template_pack=template_pack)
docs: Copy any field label to the ``placeholder`` attribute.
          Note, this method is called when :attr:`layout` is defined.