def _prompt_to_choose_backend(
    google_api_key: Optional[str],
    google_cloud_project: Optional[str],
    google_cloud_region: Optional[str],
) -> Tuple[Optional[str], Optional[str], Optional[str]]:
  """Prompts user to choose backend.

  Returns:
    A tuple of (google_api_key, google_cloud_project, google_cloud_region).
  """
  backend_choice = click.prompt(
      "1. Google AI\n2. Vertex AI\nChoose a backend",
      type=click.Choice(["1", "2"]),
  )
  if backend_choice == "1":
    google_api_key = _prompt_for_google_api_key(google_api_key)
  elif backend_choice == "2":
    click.secho(_GOOGLE_CLOUD_SETUP_MSG, fg="green")
    google_cloud_project = _prompt_for_google_cloud(google_cloud_project)
    google_cloud_region = _prompt_for_google_cloud_region(google_cloud_region)
  return google_api_key, google_cloud_project, google_cloud_region
Prompts user to choose backend.

  Returns:
    A tuple of (google_api_key, google_cloud_project, google_cloud_region).
  
src/google/adk/cli/cli_create.py