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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:
 async def list_batches(self, request):
 """Fetches list of batches from validator, optionally filtered by id. Request: query: - head: The id of the block to use as the head of the chain - id: Comma separated list of batch ids to include in results Response: data: JSON array of fully expanded Batch objects head: The head used for this query (most recent if unspecified) link: The link to this exact query, including head block paging: Paging info and nav, like total resources and a next link """

        paging_controls = self._get_paging_controls(request)
        validator_query = client_batch_pb2.ClientBatchListRequest(
            head_id=self._get_head_id(request),
            batch_ids=self._get_filter_ids(request),
            sorting=self._get_sorting_message(request, "default"),
            paging=self._make_paging_message(paging_controls))

        response = await self._query_validator(
            Message.CLIENT_BATCH_LIST_REQUEST,
            client_batch_pb2.ClientBatchListResponse,
            validator_query)

        return self._wrap_paginated_response(
            request=request,
            response=response,
            controls=paging_controls,
            data=[self._expand_batch(b) for b in response['batches']])