code: def get_bentoml_config_file_from_env() -> str | None:
      if CONFIG_ENV_VAR in os.environ:
          # User local config file for customizing bentoml
          return expand_env_var(os.environ.get(CONFIG_ENV_VAR, ""))
      return None
  
imports: from __future__ import annotations
  import importlib.metadata
  import logging
  import os
  import re
  import typing
  from functools import lru_cache
  from ...exceptions import BentoMLConfigException
  from ...exceptions import BentoMLException
label_desc: Use image node_id 4 for calling a global function with example usage: get_bentoml_config_file_from_env() and returns: None, expand_env_var