def classify_dwell(last_trip, trip):
    """
    Count the time spent at known locations by tallying the intervals between labeled points.

    :param `py:class:Trip` last_trip: An itinerum-tripkit trip object for the trip immediately prior to the provided `trip`
    :param `py:class:Trip` trip:      An itinerum-tripkit trip object
    """
    end_location = None
    for p in last_trip.points[-5:]:
        if p.label:
            end_location = p.label
            break
    start_location = None
    for p in trip.points[:5]:
        if p.label:
            start_location = p.label
            break
    if end_location and end_location == start_location:
        return end_location
