code: def gen_extra_context(self, *args):
      self.all_context[
          DatasetFieldName.SOURCE_SEQ_FIELD
      ] = self.all_src_tokens
  
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 9 for calling the Seq2SeqMetricReporter obj's underlying member method code with example usage: obj.gen_extra_context() without return types