Create nested fields for forward and reverse relationships.

def build_nested_field(self, field_name, relation_info, nested_depth):
        """
        Create nested fields for forward and reverse relationships.
        """
        class NestedSerializer(HyperlinkedModelSerializer):
            class Meta:
                model = relation_info.related_model
                depth = nested_depth - 1

        field_class = NestedSerializer
        field_kwargs = get_nested_relation_kwargs(relation_info)

        return field_class, field_kwargs