code: def _get_accuracy(self):
      num_correct = sum(
          int(p == t) for p, t in zip(self.all_preds, self.all_targets)
      )
      return num_correct / len(self.all_preds)
  
imports: from enum import Enum
  from typing import Any, Dict, List
  import numpy
  from pytext.common.constants import Stage
  from pytext.metric_reporters.channel import Channel, ConsoleChannel, FileChannel
  from pytext.metric_reporters.metric_reporter import MetricReporter
  from pytext.metrics.dense_retrieval_metrics import DenseRetrievalMetrics
label_desc: Use image node_id 8 for calling the DenseRetrievalMetricReporter obj's underlying member method code with example usage: obj._get_accuracy() and returns: unknown