How to use the haversine.Unit.KILOMETERS function in haversine

def partial_location_distance(lat1, long1, lat2, long2, threshold):
    """Given two coordinates perform a matching based on its distance using the Haversine Formula.

    Args:
        lat1: Latitude value for first coordinate point.
        lat2: Latitude value for second coordinate point.
        long1: Longitude value for first coordinate point.
        long2: Longitude value for second coordinate point.
        threshold (float): A kilometer measurement for the threshold distance between these two points.

    Returns:
        float: Number between 0.0 and 1.0 depending on match.

    """
    from haversine import haversine, Unit
    distance = haversine((lat1, long1), (lat2, long2), unit=Unit.KILOMETERS)
    result = 1 - (distance / threshold)
    logger.debug(
        "--\t\tpartial_location_distance '%s' '%s' threshold: '%s'\tresult: '%s'",
        (lat1, long1), (lat2, long2), threshold, result,
    )
    return result