code: def batch_context(self, raw_batch, batch):
      return {
          DatasetFieldName.RAW_SEQUENCE: [
              row["source_sequence"] for row in raw_batch
          ],
          BatchContext.INDEX: [
              row[RawExampleFieldName.ROW_INDEX] for row in raw_batch
          ],
      }
  
imports: from typing import Dict, List
  import torch
  from pytext.common.constants import BatchContext, DatasetFieldName, RawExampleFieldName, Stage
  from pytext.data.tensorizers import Tensorizer
  from pytext.metric_reporters.channel import Channel, ConsoleChannel, FileChannel
  from pytext.metric_reporters.metric_reporter import MetricReporter
  from pytext.metrics import safe_division
  from pytext.metrics.seq2seq_metrics import compute_f1, Seq2SeqMetrics
label_desc: Use image node_id 13 for calling the Seq2SeqMetricReporter obj's underlying member method code with example usage: obj.batch_context(raw_batch, batch) and returns: dict