How to use the pretix.base.models.Question function in pretix

qs = qs.filter(orderposition__order__status=s)

        if s not in (Order.STATUS_CANCELED, ""):
            qs = qs.filter(orderposition__canceled=False)
        if self.request.GET.get("item", "") != "":
            i = self.request.GET.get("item", "")
            qs = qs.filter(orderposition__item_id__in=(i,))

        if self.object.type == Question.TYPE_FILE:
            qs = [
                {
                    'answer': ugettext('File uploaded'),
                    'count': qs.filter(file__isnull=False).count(),
                }
            ]
        elif self.object.type in (Question.TYPE_CHOICE, Question.TYPE_CHOICE_MULTIPLE):
            qs = qs.order_by('options').values('options', 'options__answer') \
                .annotate(count=Count('id')).order_by('-count')
            for a in qs:
                a['alink'] = a['options']
                a['answer'] = str(a['options__answer'])
                del a['options__answer']
        elif self.object.type in (Question.TYPE_TIME, Question.TYPE_DATE, Question.TYPE_DATETIME):
            qs = qs.order_by('answer')
            model_cache = {a.answer: a for a in qs}
            qs = qs.values('answer').annotate(count=Count('id')).order_by('answer')
            for a in qs:
                a['alink'] = a['answer']
                a['answer'] = str(model_cache[a['answer']])
        else:
            qs = qs.order_by('answer').values('answer').annotate(count=Count('id')).order_by('-count')

.annotate(count=Count('id')).order_by('-count')
            for a in qs:
                a['alink'] = a['options']
                a['answer'] = str(a['options__answer'])
                del a['options__answer']
        elif self.object.type in (Question.TYPE_TIME, Question.TYPE_DATE, Question.TYPE_DATETIME):
            qs = qs.order_by('answer')
            model_cache = {a.answer: a for a in qs}
            qs = qs.values('answer').annotate(count=Count('id')).order_by('answer')
            for a in qs:
                a['alink'] = a['answer']
                a['answer'] = str(model_cache[a['answer']])
        else:
            qs = qs.order_by('answer').values('answer').annotate(count=Count('id')).order_by('-count')

            if self.object.type == Question.TYPE_BOOLEAN:
                for a in qs:
                    a['alink'] = a['answer']
                    a['answer'] = ugettext('Yes') if a['answer'] == 'True' else ugettext('No')
                    a['answer_bool'] = a['answer'] == 'True'
            elif self.object.type == Question.TYPE_COUNTRYCODE:
                for a in qs:
                    a['alink'] = a['answer']
                    a['answer'] = Country(a['answer']).name or a['answer']

        return list(qs)

}
                )
            )

        for q in questions:
            # Do we already have an answer? Provide it as the initial value
            answers = [a for a in pos.answerlist if a.question_id == q.id]
            if answers:
                initial = answers[0]
            else:
                initial = None
            tz = pytz.timezone(event.settings.timezone)
            help_text = rich_text(q.help_text)
            label = escape(q.question)  # django-bootstrap3 calls mark_safe
            required = q.required and not self.all_optional
            if q.type == Question.TYPE_BOOLEAN:
                if q.required:
                    # For some reason, django-bootstrap3 does not set the required attribute
                    # itself.
                    widget = forms.CheckboxInput(attrs={'required': 'required'})
                else:
                    widget = forms.CheckboxInput()

                if initial:
                    initialbool = (initial.answer == "True")
                else:
                    initialbool = False

                field = forms.BooleanField(
                    label=label, required=required,
                    help_text=help_text,
                    initial=initialbool, widget=widget,

def validate_dependency_question(self, value):
        if value:
            if value.type not in (Question.TYPE_CHOICE, Question.TYPE_BOOLEAN, Question.TYPE_CHOICE_MULTIPLE):
                raise ValidationError('Question dependencies can only be set to boolean or choice questions.')
        if value == self.instance:
            raise ValidationError('A question cannot depend on itself.')
        return value

qs = qs.filter(all_positions__item_id=fdata.get('item'), all_positions__canceled=False).distinct()

        if fdata.get('subevent'):
            qs = qs.filter(all_positions__subevent=fdata.get('subevent'), all_positions__canceled=False).distinct()

        if fdata.get('question') and fdata.get('answer') is not None:
            q = fdata.get('question')

            if q.type == Question.TYPE_FILE:
                answers = QuestionAnswer.objects.filter(
                    orderposition__order_id=OuterRef('pk'),
                    question_id=q.pk,
                    file__isnull=False
                )
                qs = qs.annotate(has_answer=Exists(answers)).filter(has_answer=True)
            elif q.type in (Question.TYPE_CHOICE, Question.TYPE_CHOICE_MULTIPLE):
                answers = QuestionAnswer.objects.filter(
                    question_id=q.pk,
                    orderposition__order_id=OuterRef('pk'),
                    options__pk=fdata.get('answer')
                )
                qs = qs.annotate(has_answer=Exists(answers)).filter(has_answer=True)
            else:
                answers = QuestionAnswer.objects.filter(
                    question_id=q.pk,
                    orderposition__order_id=OuterRef('pk'),
                    answer__exact=fdata.get('answer')
                )
                qs = qs.annotate(has_answer=Exists(answers)).filter(has_answer=True)

        if fdata.get('status') == 'overpaid':
            qs = Order.annotate_overpayments(qs, refunds=False, results=False, sums=True)

((str(op.seat) + " / ") if op.seat else "") +
                          money_filter(op.price, self.event.currency), self.get_style()),
            ]
            acache = {}
            if op.addon_to:
                for a in op.addon_to.answers.all():
                    # We do not want to localize Date, Time and Datetime question answers, as those can lead
                    # to difficulties parsing the data (for example 2019-02-01 may become Février, 2019 01 in French).
                    if a.question.type in Question.UNLOCALIZED_TYPES:
                        acache[a.question_id] = a.answer
                    else:
                        acache[a.question_id] = str(a)
            for a in op.answers.all():
                # We do not want to localize Date, Time and Datetime question answers, as those can lead
                # to difficulties parsing the data (for example 2019-02-01 may become Février, 2019 01 in French).
                if a.question.type in Question.UNLOCALIZED_TYPES:
                    acache[a.question_id] = a.answer
                else:
                    acache[a.question_id] = str(a)
            for q in questions:
                txt = acache.get(q.pk, '')
                p = Paragraph(txt, self.get_style())
                while p.wrap(colwidths[len(row)], 5000)[1] > 50 * mm:
                    txt = txt[:len(txt) - 50] + "..."
                    p = Paragraph(txt, self.get_style())
                row.append(p)
            if op.order.status != Order.STATUS_PAID:
                tstyledata += [
                    ('BACKGROUND', (2, len(tdata)), (2, len(tdata)), '#990000'),
                    ('TEXTCOLOR', (2, len(tdata)), (2, len(tdata)), '#ffffff'),
                    ('ALIGN', (2, len(tdata)), (2, len(tdata)), 'CENTER'),
                ]

def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['items'].queryset = self.instance.event.items.all()
        self.fields['items'].required = True
        self.fields['dependency_question'].queryset = self.instance.event.questions.filter(
            type__in=(Question.TYPE_BOOLEAN, Question.TYPE_CHOICE, Question.TYPE_CHOICE_MULTIPLE),
            ask_during_checkin=False
        )
        if self.instance.pk:
            self.fields['dependency_question'].queryset = self.fields['dependency_question'].queryset.exclude(
                pk=self.instance.pk
            )
        self.fields['identifier'].required = False
        self.fields['dependency_values'].required = False
        self.fields['help_text'].widget.attrs['rows'] = 3

]
            if len(name_scheme['fields']) > 1:
                for k, label, w in name_scheme['fields']:
                    row.append(
                        op.attendee_name_parts.get(k, '')
                    )
            row += [
                op.attendee_email,
                op.voucher.code if op.voucher else '',
                op.pseudonymization_id,
            ]
            acache = {}
            for a in op.answers.all():
                # We do not want to localize Date, Time and Datetime question answers, as those can lead
                # to difficulties parsing the data (for example 2019-02-01 may become Février, 2019 01 in French).
                if a.question.type in Question.UNLOCALIZED_TYPES:
                    acache[a.question_id] = a.answer
                else:
                    acache[a.question_id] = str(a)
            for q in questions:
                row.append(acache.get(q.pk, ''))
            try:
                row += [
                    order.invoice_address.company,
                    order.invoice_address.name,
                ]
                if len(name_scheme['fields']) > 1:
                    for k, label, w in name_scheme['fields']:
                        row.append(
                            order.invoice_address.name_parts.get(k, '')
                        )
                row += [

def get_object(self, queryset=None) -> Question:
        try:
            return self.request.event.questions.get(
                id=self.kwargs['question']
            )
        except Question.DoesNotExist:
            raise Http404(_("The requested question does not exist."))