docs: def get_config(k: str) -> Any:
      """
      Returns a configuration variable's value or None if it is unset.
      """
      # If the config has been set explicitly, use it.
      if k in list(CONFIG.keys()):
          return CONFIG[k]
  
      # If there is a specific PULUMI_CONFIG_<k> environment variable, use it.
      env_key = get_config_env_key(k)
      if env_key in os.environ:
          return os.environ[env_key]
  
      # If the config hasn't been set, but there is a process-wide PULUMI_CONFIG environment variable, use it.
      env_dict = get_config_env()
      if env_dict is not None and k in list(env_dict.keys()):
          return env_dict[k]
  
      return None