MultipleChoiceField doesn't use default value if not required

[RukosenpaIneligible]

I have some serializer using for validation of query parameters

class ReportArgumentsSerializer(serializers.Serializer):
    date_start = serializers.DateField(required=False, default=date(2022, 5, 10))
    date_end = serializers.DateField(required=False, default=date(2022, 5, 20))
    classes_numbers = serializers.MultipleChoiceField(
        required=True,
        choices=range(1, 12),
        default=set(range(1, 12))
    )

    def create(self, validated_data):
        pass

    def update(self, instance, validated_data):
        pass

So, if i try to pass an empty QueryDict()(reminder: request.query_params also generate QueryDict) instance as an argument to that serializer i expect to get validated data with default values like this:

serializer = ReportArgumentsSerializer(data=QueryDict())
serializer.is_valid()
serializer.validated_data

and response:

OrderedDict([('date_start', datetime.date(2022, 5, 10)),
             ('date_end', datetime.date(2022, 5, 20)),
             ('classes_numbers', set(1, 2, ... , 10, 11 ))])

But instead i got this:

OrderedDict([('date_start', datetime.date(2022, 5, 10)),
             ('date_end', datetime.date(2022, 5, 20)),
             ('classes_numbers', set())])

But this doesn't happen because in this string we call getlist method of QueryDict without passing default argument, so it will call with default=None argument. As a result this string executes, and we get empty list instead.
Then when we run validators in this string we call validate_empty_values method which returns default values for all kind of serializer fields. But this triggers only if passed data is empty constant. In this serializer setup we never get our default value because conditions for its triggering never occurs.