def _to_epoch_time(date):
    """Convert a `datetime` object to an integer number of seconds since
    the (local) Unix epoch.
    """
    if hasattr(date, 'timestamp'):
        # The `timestamp` method exists on Python 3.3+.
        return int(date.timestamp())
    else:
        epoch = datetime.fromtimestamp(0)
        delta = date - epoch
        return int(delta.total_seconds())