Поезд

from solution import Train, Wagon
 
w1, w2, w3 = Wagon(1), Wagon(2), Wagon(3)
tr = Train(206)
tr.append(w1)
tr.append(w3)
tr.append(w2)
for item in tr:
    print(item)
print(f"This train has number {tr.get_number()}.")
tr[1] = Wagon(5)
del tr[2]
print(tr[-1])

from solution import Train, Wagon
 
tr = Train(206, [Wagon(1), Wagon(2), Wagon(3)])
print(', '.join([str(item.get_number()) for item in tr]))
print(f"This train has number {tr.get_number()}.")
for i in range(4, 10):
    tr.append(Wagon(i))
print(*tr.get_wagons())

class Wagon:
    def __init__(self, number):
        self.number = number
 
    def __str__(self):
        return f'№{self.number}'
 
    def get_number(self):
        return self.number
 
 
class Train:
    def __init__(self, number, wagons=None):
        self.number = number
        self.wagons = wagons if wagons is not None else []
 
    def get_number(self):
        return self.number
 
    def get_wagons(self):
        return self.wagons
 
    def append(self, item):
        self.wagons.append(item)
 
    def __len__(self):
        return len(self.wagons)
 
    def __str__(self):
        return f'Train {self.number} has {len(self.wagons)} wagons'
 
    def __getitem__(self, key):
        return self.wagons[key]
 
    def __setitem__(self, key, value):
        self.wagons[key] = value
 
    def __delitem__(self, key):
        if key == len(self.wagons) - 1:
            del self.wagons[key]
 
    def __iter__(self):
        return iter(self.wagons)