docstr: Check if a file corresponding to this cross_experiment_key already exists
  
  Returns
  -------
  Boolean
docstr_tok: ["Check","if","a","file","corresponding","to","this","cross_experiment_key","already","exists","Returns","--","--","--","-","Boolean"]
code: def does_key_exist(self):
      """Check if a file corresponding to this cross_experiment_key already exists
  
      Returns
      -------
      Boolean"""
      tested_keys_dir_contents = [
          os.path.splitext(_)[0] for _ in listdir(self.tested_keys_dir)
      ]
      self.exists = self.key in tested_keys_dir_contents
  
      return self.exists
  
imports: from hyperparameter_hunter.feature_engineering import FeatureEngineer, EngineerStep
  from hyperparameter_hunter.i_o.exceptions import EnvironmentInvalidError, EnvironmentInactiveError
  from hyperparameter_hunter.keys.hashing import make_hash_sha256
  from hyperparameter_hunter.compat.keras_helper import keras_callback_to_dict, keras_initializer_to_dict, parameterize_compiled_keras_model
  from hyperparameter_hunter.compat.keras_optimization_helper import initialize_dummy_model
  from hyperparameter_hunter.metrics import Metric
  from hyperparameter_hunter.sentinels import Sentinel
  from hyperparameter_hunter.settings import G
  from hyperparameter_hunter.utils.file_utils import write_json, read_json, add_to_json, make_dirs
  from hyperparameter_hunter.utils.file_utils import RetryMakeDirs
  from hyperparameter_hunter.utils.general_utils import subdict
  from hyperparameter_hunter.utils.boltons_utils import remap, default_enter
  from abc import ABCMeta, abstractmethod
  from copy import deepcopy
  from functools import partial
  from inspect import isclass, getsource
  from os import listdir
  import os.path
  import pandas
  import shelve
label_desc: Use image node_id 2 for calling the CrossExperimentKeyMaker obj's underlying member method code with example usage: obj.does_key_exist() and returns: self