code: def delete(self, key: str) -> int:
      key = self.__concat_key_with_prefixes(key)
      ret = internal_kv._internal_kv_del(key)
      return ret
  
imports: import asyncio
  import time
  from typing import List
  import numpy
  import ray
  import ray.experimental.internal_kv
  from ray._raylet import GcsClient
  from ray.util.collective.types import ReduceOp, torch_available
  from ray.util.queue import _QueueActor
label_desc: Use image node_id 4 for calling the RayInternalKvStore obj's underlying member method code with example usage: obj.delete(key) and returns: ret