code: def test_active_children(self):
      # Reset fiber module so other processes won't inteference with
      # current run
      import importlib
  
      importlib.reload(fiber)
      fiber.process._children = set()
      try:
          p1 = Process(
              target=time.sleep, args=(1,), name="test_active_children1"
          )
          p1.start()
          p2 = Process(
              target=time.sleep, args=(1,), name="test_active_children2"
          )
          p2.start()
          assert len(fiber.active_children()) == 2
      finally:
          p1.join()
          p2.join()
  
file_path: fiber/tests/test_process_misc.py
imports: import pytest
  import time
  import fiber
  from fiber import Process
  from fiber.queues import Pipe, SimpleQueue
  import docker
label_desc: Use image node_id 2 for calling the TestMisc obj's underlying member method code with example usage: obj.test_active_children() without return types