from functools import reduce
class MyList:
    def __init__(self, *args):
        self.items = list(args)

    def __len__(self):
        return reduce(lambda acc, x: acc + (sum(x) if hasattr(x, '__iter__') else x), [x*2 for x in self.items])

my_list = MyList(1, 2, 3, [4, 5])
print(len(my_list))

a = {1, 2, 9}
b = {2, 3, 9}
c = a & b
c.remove(2)
print(*c)

a = {1, 2}
b = {2, 3}
c = (a | b) - (a & b)
d = a ^ b
print(c == d)

a, b = {1, 2}, {2, 3}
c = a - b
d = b - a
print(*(c & d), *(c | d))

my_list = [1, 2, 3, 4, 5]
r = [x % 3 for x in my_list]
print(sum(r))

class A:
    __x = 1
    def f(self):
        return "f from A"
    
    def g(self):
        return "g from A"

class B:
    __x = 2
    def f(self):
        return "f from B"
    
    def g(self):
        return "g from B"

class C(A, B):
    f = B.f
    
c = C()
print(c.f(), c.g(), c._A__x, c._B__x)

def intersect(*seqs):
    if len(seqs) > 2:
        return intersect(seqs[0], intersect(*seqs[1:]))
    seq1, seq2 = seqs[0], seqs[1]
    res = []
    for x in seq1:
        if x in seq2:
            res.append(x)    
    return res

x = intersect([1, 2, "a", "b"], (1, 4, "b"), {1, "b", "c"}) 
print(x)

def f(n):
    return 0 if n == 0 else 2**n + f(n-1)
print(f(3))

def f():
    x = 1
    y = 1
    def g():
        nonlocal x
        x, y = 2, 2
    g()
    print(x, y)

f()

try:
    my_x = 1
    raise Exception('exception')  #1
except Exception as my_err:
    print(my_err)                 #2
    my_y = 2
print(my_x)                       #3
print(my_y)                       #4
print(my_err)                     #5