code: def test_child_thread_isolation():
      """Child threads have isolated environments"""
  
      def func(key, value, other_key):
          env = {key: value}
          with rio.Env(**env):
              assert get_gdal_config(key) == value
              # The other key is one set in another child thread.
              assert get_gdal_config(other_key) is None
  
      t1 = Thread(target=func, args=("is_t1", True, "is_t2"))
      t2 = Thread(target=func, args=("is_t2", True, "is_t1"))
  
      t1.start()
      t2.start()
      t1.join()
      t2.join()
  
file_path: rasterio/tests/test_threading.py
imports: from threading import Thread
  import time
  import unittest
  import rasterio
  from rasterio.env import get_gdal_config
label_desc: Use image node_id 2 for calling a global function with example usage: test_child_thread_isolation() without return types