def METHOD_NAME(self, entry, eta=None, priority=0, time=monotonic):
    """Enter function into the scheduler.
    Arguments:
    ---------
        entry (~kombu.asynchronous.timer.Entry): Item to enter.
        eta (datetime.datetime): Scheduled time.
        priority (int): Unused.
    """
    if eta is None:
        eta = time()
    if isinstance(eta, datetime):
        try:
            eta = to_timestamp(eta)
        except Exception as exc:
            if not self.handle_error(exc):
                raise
            return
    return self._enter(eta, priority, entry)