Display a prompt and wait for a response.

    Args:
      message: A string to be presented to the user.
      text_input: A boolean indicating whether the user must respond with text.
      timeout_s: Seconds to wait before raising a PromptUnansweredError.
      cli_color: An ANSI color code, or the empty string.

    Returns:
      A string response, or the empty string if text_input was False.

    Raises:
      MultiplePromptsError: There was already an existing prompt.
      PromptUnansweredError: Timed out waiting for the user to respond.

def prompt(self, message, text_input=False, timeout_s=None, cli_color=''):
    """Display a prompt and wait for a response.

    Args:
      message: A string to be presented to the user.
      text_input: A boolean indicating whether the user must respond with text.
      timeout_s: Seconds to wait before raising a PromptUnansweredError.
      cli_color: An ANSI color code, or the empty string.

    Returns:
      A string response, or the empty string if text_input was False.

    Raises:
      MultiplePromptsError: There was already an existing prompt.
      PromptUnansweredError: Timed out waiting for the user to respond.
    """
    self.start_prompt(message, text_input, cli_color)
    return self.wait_for_prompt(timeout_s)