class_docstr: Represents an actor method invocation in a Ray function DAG.
code: def _get_actor_handle(self) -> Optional["ray.actor.ActorHandle"]:
      if not isinstance(self._parent_class_node, ray.actor.ActorHandle):
          return None
      return self._parent_class_node
  
imports: from weakref import ReferenceType
  import ray
  from ray.dag.dag_node import DAGNode
  from ray.dag.input_node import InputNode
  from ray.dag.format_utils import get_dag_node_str
  from ray.dag.constants import PARENT_CLASS_NODE_KEY, PREV_CLASS_METHOD_CALL_KEY
  from ray.util.annotations import DeveloperAPI
  from typing import Any, Dict, List, Union, Tuple, Optional
label_desc: Use image node_id 7 for calling the ClassMethodNode obj's underlying member method code with example usage: obj._get_actor_handle() and returns: self, None