code: def is_terminated(self, node_id):
      if node_id is None:
          # Circumvent test-cases where there's no head node.
          return True
      with self.lock:
          return self.mock_nodes[node_id].state in [
              "stopped",
              "terminated",
          ]
  
imports: import re
  import threading
  from subprocess import CalledProcessError
  from typing import Callable, Dict, List, Optional
  from ray.autoscaler.node_provider import NodeProvider
label_desc: Use image node_id 5 for calling the MockProvider obj's underlying member method code with example usage: obj.is_terminated(node_id) and returns: True, unknown