class_docstr: Helper class for defining % of episodes where a given agent type has exactly
  repeated the same utterance.
code: def get_episode_metrics(self) -> Optional[Dict[str, Metric]]:
      repeat = int(self.repeated)
      self.repeated = False
      self.turns = []
      return {self.metric_key(): AverageMetric(repeat)}
  
imports: from parlai.core.message import Message
  from parlai.core.metrics import Metric, AverageMetric, normalize_answer, BleuMetric, SumMetric
  from parlai.core.tod.tod_core import STANDARD_API_NAME_SLOT, STANDARD_REQUIRED_KEY, STANDARD_OPTIONAL_KEY, STANDARD_API_SCHEMAS
  from typing import Dict, List, Optional, Tuple
  from parlai.core.tod.world_metrics_handlers import TodMetricsHandler, register_metrics_handler, _ApiCallGoalInteractionHelper, goals_hit_helper
label_desc: Use image node_id 4 for calling the _ExactRepeatMetricsHandler obj's underlying member method code with example usage: obj.get_episode_metrics() and returns: dict