code: def delete(self, key: str) -> bool:
      if not isinstance(key, str):
          raise TypeError(
              "key must be a string, got: {}.".format(type(key))
          )
  
      if key in self.store:
          del self.store[key]
          return True
  
      return False
  
file_path: ray/python/ray/serve/tests/unit/test_endpoint_state.py
imports: import sys
  from typing import Any, Tuple
  from unittest.mock import Mock, patch
  import pytest
  from ray.serve._private.endpoint_state import EndpointState
label_desc: Use image node_id 4 for calling the MockKVStore obj's underlying member method code with example usage: obj.delete(key) and returns: False, True