def METHOD_NAME(
    self,
    base_quote: BaseQuote,
    date: datetime.date | None = None,
) -> PricePoint | tuple[None, Decimal] | tuple[None, None]:
    """Get the price point for the given currency pair."""
    base, quote = base_quote
    if base == quote:
        return (None, ONE)
    price_list = self._map.get(base_quote)
    if price_list is None:
        return (None, None)
    if date is None:
        return price_list[-1]
    index = bisect(DateKeyWrapper(price_list), date)
    if index == 0:
        return (None, None)
    return price_list[index - 1]