code: def _set_option(key: str, value: Any, where_defined: str) -> None:
      """Set a config option by key / value pair.
  
      This function assumes that the _config_options dictionary has already been
      populated and thus should only be used within this file and by tests.
  
      Parameters
      ----------
      key : str
          The key of the option, like "logger.level".
      value
          The value of the option.
      where_defined : str
          Tells the config system where this was set.
  
      """
      assert (
          _config_options is not None
      ), "_config_options should always be populated here."
      if key not in _config_options:
          # Import logger locally to prevent circular references
          from streamlit.logger import get_logger
  
          LOGGER = get_logger(__name__)
  
          LOGGER.warning(
              f'"{key}" is not a valid config option. If you previously had this config option set, it may have been removed.'
          )
  
      else:
          _config_options[key].set_value(value, where_defined)
  
imports: import copy
  import os
  import secrets
  import threading
  from collections import OrderedDict
  from typing import Any, Callable, Dict, Optional, cast
  import toml
  from blinker import Signal
  from streamlit import config_util, development, env_util, file_util, util
  from streamlit.config_option import ConfigOption
  from streamlit.errors import StreamlitAPIException
label_desc: Use image node_id 19 for calling a global function with example usage: _set_option(key, value, where_defined) without return types