code: def _get_allowed_hosts() -> str:
      """Returns a comma separated list of host[:port] that should be allowed to connect."""
      # TODO: Enable only lightning.ai domain in the cloud
      return "*"
  
imports: from __future__ import annotations
  import inspect
  import os
  import pathlib
  import subprocess
  import sys
  from typing import Callable, TextIO
  from lightning.app.frontend.frontend import Frontend
  from lightning.app.frontend.utils import _get_frontend_environment
  from lightning.app.utilities.app_helpers import Logger
  from lightning.app.utilities.cloud import is_running_in_cloud
  from lightning.app.utilities.imports import requires
  from lightning.app.utilities.log import get_logfile
label_desc: Use image node_id 2 for calling a global function with example usage: _get_allowed_hosts() and returns: str