code: def __getattr__(self, key: str):
      val = self._value_list_observers.get(key, None)
      if val is not None:
          return val
      val = self._aggregating_observers.get(key, None)
      if val is not None:
          return val.aggregator
      raise AttributeError
  
file_path: ReAgent/reagent/reporting/reporter_base.py
imports: import abc
  import logging
  from typing import Dict
  import torch
  from reagent.core.observers import CompositeObserver, EpochEndObserver, IntervalAggregatingObserver, ValueListObserver
  from reagent.core.result_registries import TrainingReport
  from reagent.core.tracker import ObservableMixin
  from reagent.core.utils import lazy_property
label_desc: Use image node_id 4 for calling the ReporterBase obj's underlying member method code with example usage: obj.__getattr__(key) and returns: val, val