code: def update(self, key: str, value):
      if key == "epoch_end":
          self.flush()
          return
      self.intermediate_values.append(value)
      self.iteration += 1
      if self.interval and self.iteration % self.interval == 0:
          logger.info(
              "Aggregating values over the recent interval for %s at iteration %s; aggregator: %s",
              self.key,
              self.iteration,
              self.aggregator.__class__.__name__,
          )
          self.aggregator(self.key, self.intermediate_values)
          self.intermediate_values = []
  
imports: import logging
  from typing import Any, Dict, Iterable, List, Optional
  from reagent.core.tensorboardX import SummaryWriterContext
  from reagent.core.tracker import Aggregator, Observer
label_desc: Use image node_id 2 for calling the IntervalAggregatingObserver obj's underlying member method code with example usage: obj.update(key, value) without return types