def unsubscribe(id_or_symbols):
    """
    取消订阅合约行情。取消订阅会导致合约池内合约的减少，如果当前合约池中没有任何合约，则策略直接退出。

    :param id_or_symbols: 标的物
    :type id_or_symbols: :class:`~Instrument` object | `str` | List[:class:`~Instrument`] | List[`str`]
    """
    current_universe = Environment.get_instance().get_universe()
    if isinstance(id_or_symbols, six.string_types):
        order_book_id = instruments(id_or_symbols).order_book_id
        current_universe.discard(order_book_id)
    elif isinstance(id_or_symbols, Instrument):
        current_universe.discard(id_or_symbols.order_book_id)
    elif isinstance(id_or_symbols, Iterable):
        for item in id_or_symbols:
            i = assure_order_book_id(item)
            current_universe.discard(i)
    else:
        raise RQInvalidArgument(_(u"unsupported order_book_id type"))

    Environment.get_instance().update_universe(current_universe)