def METHOD_NAME(_env: MutableMapping[str, str] | None = None) -> int:
    environ = _env if _env is not None else getattr(os, 'environb', os.environ)
    size = 8 * len(environ)  # number of pointers in `envp`
    for k, v in environ.items():
        size += len(k) + len(v) + 2  # c strings in `envp`
    return size