code: def get_fields(self):
          
          field_mapping = OrderedDict()
          for field, data in self.instance.items():
              field_mapping.update(
                  {field: self.facet_dict_field_class(
                      child=self.facet_list_field_class(child=self.facet_field_serializer_class(data)), required=False)}
              )
  
          if self.serialize_objects is True:
              field_mapping["objects"] = serializers.SerializerMethodField()
  
          return field_mapping
docs: This returns a dictionary containing the top most fields,
          ``dates``, ``fields`` and ``queries``.