async def should_update_bikes(delta: timedelta):
    """
    Checks the most recently cached bike and returns true if
    it either doesn't exist or
    :return: Whether the cache should be updated.

    todo what if there are no bikes added for a week? ... every request will be triggered.
    """
    bike = Bike.get_most_recent_bike()
    if bike is not None:
        return bike.cached_date < datetime.now() - delta
    else:
        return True
Checks the most recently cached bike and returns true if
    it either doesn't exist or
    :return: Whether the cache should be updated.

    todo what if there are no bikes added for a week? ... every request will be triggered.