code: def tracker() -> NodeProviderAvailabilityTracker:
      global cur_time
      cur_time = 1
  
      def get_time():
          global cur_time
          return cur_time
  
      return NodeProviderAvailabilityTracker(
          timer=get_time, ttl=60 * 30
      )
  
file_path: ray/python/ray/tests/test_node_provider_availability_tracker.py
imports: import datetime
  import dataclasses
  import os
  import sys
  import pytest
  from ray.autoscaler.node_launch_exception import NodeLaunchException
  from ray.autoscaler._private.node_provider_availability_tracker import NodeProviderAvailabilityTracker, NodeAvailabilitySummary, NodeAvailabilityRecord, UnavailableNodeInformation
label_desc: Use image node_id 1 for calling a global function with example usage: tracker() and returns: NodeProviderAvailabilityTracker, cur_time