code: def test_environment_end():
      """Make sure that in the end ray hasn't been started"""
      assert not ray.is_initialized()
  
file_path: ray/python/ray/serve/tests/test_deployment_graph_handle_serde.py
imports: import sys
  import pytest
  import ray
  from ray import serve
  from ray.serve._private.deployment_graph_build import build
  from ray.serve.dag import InputNode
label_desc: Use image node_id 7 for calling a global function with example usage: test_environment_end() without return types