def get_fields(self):
        """
        Get the required fields for serializing the result.
        """

        fields = self.Meta.fields
        exclude = self.Meta.exclude
        ignore_fields = self.Meta.ignore_fields
        indices = self.Meta.index_classes

        declared_fields = copy.deepcopy(self._declared_fields)
        prefix_field_names = len(indices) > 1
        field_mapping = OrderedDict()

        # overlapping fields on multiple indices is supported by internally prefixing the field
        # names with the index class to which they belong or, optionally, a user-provided alias
        # for the index.
        for index_cls in self.Meta.index_classes:
            prefix = ""
            if prefix_field_names:
                prefix = "_%s__" % self._get_index_class_name(index_cls)
            for field_name, field_type in six.iteritems(index_cls.fields):
                orig_name = field_name
                field_name = "%s%s" % (prefix, field_name)

                # Don't use this field if it is in `ignore_fields`
                if orig_name in ignore_fields or field_name in ignore_fields:
                    continue
                # When fields to include are decided by `exclude`
                if exclude:
                    if orig_name in exclude or field_name in exclude:
                        continue
                # When fields to include are decided by `fields`
                if fields:
                    if orig_name not in fields and field_name not in fields:
                        continue

                # Look up the field attributes on the current index model,
                # in order to correctly instantiate the serializer field.
                model = index_cls().get_model()
                kwargs = self._get_default_field_kwargs(model, field_type)
                kwargs['prefix_field_names'] = prefix_field_names
                field_mapping[field_name] = self._field_mapping[field_type](**kwargs)

        # Add any explicitly declared fields. They *will* override any index fields
        # in case of naming collision!.
        if declared_fields:
            for field_name in declared_fields:
                field_mapping[field_name] = declared_fields[field_name]
        return field_mapping
Get the required fields for serializing the result.