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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_fields(self):
 """ This returns a dictionary containing the top most fields, ``dates``, ``fields`` and ``queries``. """

        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