Raise code

def read_env_file(
    file_path: StrPath, *, encoding: str = None, case_sensitive: bool = False
) -> Dict[str, Optional[str]]:
    try:
        from dotenv import dotenv_values
    except ImportError as e:
        raise ImportError('python-dotenv is not installed, run `pip install pydantic[dotenv]`') from e

    file_vars: Dict[str, Optional[str]] = dotenv_values(file_path, encoding=encoding or 'utf8')
    if not case_sensitive:
        return {k.lower(): v for k, v in file_vars.items()}
    else:
        return file_vars