def _prompt_for_google_api_key(
    google_api_key: Optional[str],
) -> str:
  """Prompts user for Google API key."""
  google_api_key = google_api_key or os.environ.get("GOOGLE_API_KEY", None)

  google_api_key = _prompt_str(
      "Enter Google API key",
      prior_msg=_GOOGLE_API_MSG,
      default_value=google_api_key,
  )
  return google_api_key
Prompts user for Google API key.
src/google/adk/cli/cli_create.py