Django Inline Admin Formset extra entry has prefix instead of number
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I have an admin form that allows and end user to add a quiz, and the quiz has answers. When you edit the quiz, the quiz answer section has 4 lines for quiz answers. The first 3 are numbered 0, 1, 2 and the fourth is `__prefix__`. 

Example:

    <input name="quizanswer_set-0-text" value="one" class="vTextField" maxlength="255" type="text" id="id_quizanswer_set-0-text" />

    <input id="id_quizanswer_set-__prefix__-text" type="text" class="vTextField" name="quizanswer_set-__prefix__-text" maxlength="255" />

When the form is processed, it skips the fourth input because, I'm assuming, the prefix is not what it is looking for.

Template Code:

    {% for inline_admin_form in inline_admin_formset %}
    {{ inline_admin_form.pk_field.field }} {{ inline_admin_form.fk_field.field }}


Form:

    class QuizAnswerInlineFormSet(forms.models.BaseInlineFormSet):
        def is_valid(self):
            # make sure errors are populated
            _ = self.errors
        
            return super(QuizAnswerInlineFormSet, self).is_valid()            

        def clean(self):
            super(QuizAnswerInlineFormSet, self).clean()
        
            answer_count = 0
            correct_count = 0

            for form in self.forms:
                if not hasattr(form, 'cleaned_data'):
                    continue
                if not form.cleaned_data:
                    continue
                if not form.is_valid():
                    continue
                if form.cleaned_data[forms.formsets.DELETION_FIELD_NAME]:
                    continue
            
                answer_count += 1
            
                if form.cleaned_data.get("is_correct", False):
                    correct_count += 1
        
            if answer_count < 2:
                raise ValidationError("Questions must have at least 2 answers")
        
            if correct_count != 1:
                raise ValidationError("There must be exactly one correct answer")


Does anyone have an idea of why this would be printing `__PREFIX__` rather than a number? Is there something I need to set for this? I didn't originally make the form, I'm just trying to fix it and I'm not overly familiar with this type of form.