def get_truck_number(trip):
    """
    Return the Truck number
    :param trip: Object
    :return: string containing truck number
    """
    truck_number = ''
    if 'truck_number' in trip.keys():
        truck_number = trip['truck_number']
    if truck_number == '':
        try:
            truck_number = trip['vehicle']
        except KeyError as e:
            truck_number = ''
    return truck_number
