          UniquenessTogetherModel.objects.create(
              race_name=None,
              position=None
          )
          data = {'race_name': None, 'position': None}
          serializer = UniquenessTogetherSerializer(data=data)
  
          assert serializer.is_valid()
  
  
  # Tests for `UniqueForDateValidator`
  # ----------------------------------
 
</s> remove         UniquenessTogetherModel.objects.create(
            race_name=None,
 </s> add         # None values that are on fields which are part of the uniqueness
        # constraint cause the instance to ignore uniqueness validation.
        NullUniquenessTogetherModel.objects.create(
            date_of_birth=datetime.date(2000, 1, 1),
            race_name='Paris Marathon', </s> remove         if None not in attrs.values() and queryset.exists():
 </s> add         checked_values = [
            value for field, value in attrs.items() if field in self.fields
        ]
        if None not in checked_values and queryset.exists():
        data = {
            'date': datetime.date(2000, 1, 1),
            'race_name': 'Paris Marathon',
            'position': None
        }
        serializer = NullUniquenessTogetherSerializer(data=data)
          UniquenessTogetherModel.objects.create(
              race_name=None,
              position=None
          )
        data = {
            'date': datetime.date(2000, 1, 1),
            'race_name': 'Paris Marathon',
            'position': None
        }
        serializer = NullUniquenessTogetherSerializer(data=data)
        data = {
            'date': datetime.date(2000, 1, 1),
            'race_name': 'Paris Marathon',
            'position': None
        }
        serializer = NullUniquenessTogetherSerializer(data=data)
        data = {
            'date': datetime.date(2000, 1, 1),
            'race_name': 'Paris Marathon',
            'position': None
        }
        serializer = NullUniquenessTogetherSerializer(data=data)
          assert serializer.is_valid()
  
  
  # Tests for `UniqueForDateValidator`
  # ----------------------------------
keep keep keep keep replace replace replace keep keep keep keep keep
 Skip validation of NULL field only if it part of unique_together 
tests/test_validators.py