class_docstr: Actor to make resource requests to autoscaler for the datasets.
  
  The resource requests are set to timeout after RESOURCE_REQUEST_TIMEOUT seconds.
  For those live requests, we keep track of the last request made for each execution,
  which overrides all previous requests it made; then sum the requested amounts
  across all executions as the final request to the autoscaler.
code: def purge_expired_requests(self):
      self._purge()
      ray.autoscaler.sdk.request_resources(
          bundles=self._aggregate_requests()
      )
  
file_path: ray/python/ray/data/_internal/execution/autoscaling_requester.py
imports: import math
  import threading
  import time
  from typing import Dict, List
  import ray
  from ray.data.context import DataContext
  from ray.util.scheduling_strategies import NodeAffinitySchedulingStrategy
label_desc: Use image node_id 2 for calling the AutoscalingRequester obj's underlying member method code with example usage: obj.purge_expired_requests() without return types