code: def calculate_metric(self) -> DenseRetrievalMetrics:
      average_rank, mean_reciprocal_rank = self._get_ranking_metrics()
      return DenseRetrievalMetrics(
          num_examples=len(self.all_preds),
          accuracy=self._get_accuracy(),
          average_rank=average_rank,
          mean_reciprocal_rank=mean_reciprocal_rank,
      )
  
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 6 for calling the DenseRetrievalMetricReporter obj's underlying member method code with example usage: obj.calculate_metric() and returns: DenseRetrievalMetrics