def sum_valid_rooms(valid_rooms):
    """
    Get the sum of all the sector IDs in valid rooms.

    Args:
        valid_rooms (list):     List containting tuples of valid rooms.

    Returns:
        int
    """
    # Valid Room:
    #   (room_name, sector_id, checksum)
    return sum([i[1] for i in valid_rooms])