def modify(x, y=[]):
    y.append(x)
    return sum(y)

result = modify(5) + modify(7) + modify(4)
print(result)

class A:
    def __new__(cls):
        return 42
        
    def __init__(self):
        print("Init")

print(A())

class A:
    def __init__(self):
        self.__x = 1
        
    def get_x(self):
        return self.__x

class B(A):
    def __init__(self):
        super().__init__()
        self.__x = 2

b = B()
print(b.get_x())

lst = [x for x in range(10) if x % 2 == 0 if x % 3 == 0]
print(lst)

def modify(x, y=[]):
    y.append(x)
    return sum(y)

result = modify(5) + modify(7) + modify(4)
print(result)

a = [[1, 2], [3, 4]]
b = list(a)
a[0][1] = 5
print(b[0][1])

class Model:
    val = 1
    lst = [val for _ in range(3)]

print(Model.lst)

a = [[1, 2], [3, 4]]
b = list(a)
a[0][1] = 5
print(b[0][1])

def add_item(num, lst=[]):
    lst.append(num)
    return lst

add_item(1)
print(add_item(2))

class A:
    x = 1

class B(A):
    pass

class C(A):
    pass

B.x = 2
A.x = 3

print(C.x)