a = "Xmas"
b = a
a = "New Year"
print((a is b))

s = [1, 2, 1]
print(s.index(1), s.index(2))

s = [1, 2, 1, 1, 1, 3]
print(s.count(1) + s.index(2))

x = [0, None, 1]
y = []
s = (any(x), any(y)) == (all(y), all(x))
print(s)

x = [0, None]
y = ["abc", 1]
s = (any(x), any(y)) == (all(x), all(y))
print(s)

class A:
    def f(self):
        print('A', end="")
class B:
    def f(self):
        print('B', end="")
class C(A):
    def f(self):
        print("C", end="")
        super().f()
        self.__class__.__bases__ = (B,)
x = C()
_ = x.f(), x.f()

class B:
    def __init__(self) : 
        print ('В', end='')
        super().__init__()
class C:
    def __init__(self): 
        print('C', end='')
        super().__init__ ()
class D(B, C):
    def __init__(self):
        print('D', end='') 
        B.__init__(self)
        C.__init__(self)
X = D()

class A:
    def f(self):
        print("A", end="")
class B(A):
    def f(self):
        print("B", end="")
        super().f()
        A.f(self)
class C(A):
    def f(self):
        print("C", end="")
        super().f()
        A.f(self)
class D(B, C):
    def f(self):
        print("D", end="")
        super().f()
d = D()
d.f()

class A:
    x = 1
    l = []
a1, a2 = A(), A()
a1.x = 2
a1.l.append(100)
print(a2.x, len(a2.l))