def symmetric_tour_list(n_cities, start_index = 0):
    """
    Returns a numpy array representiung a symmetric tour of cities
    length = n_cities + 1
    First and last cities are index 'start_index' e.g. for
    start_index = 0 then for 5 cities tour = 
    [0, 1, 2, 3, 4, 0]
    """
    tour = [x for x in range(n_cities)]
    tour.remove(start_index)
    tour.insert(0, start_index)
    tour.append(start_index)
    return tour