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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 call(self, items, additional_fields, shape):
 """ Returns all items in an account that correspond to a list of ID's, in stable order. :param items: a list of (id, changekey) tuples or Item objects :param additional_fields: the extra fields that should be returned with the item, as FieldPath objects :param shape: The shape of returned objects :return: XML elements for the items, in stable order """

        return self._pool_requests(payload_func=self.get_payload, **dict(
            items=items,
            additional_fields=additional_fields,
            shape=shape,
        ))