lst = [10, 20, 30, 40, 50]
del lst[1::2]
print(lst)

gen = (x for x in range(3))
print(list(gen), list(gen))

keys = ['a', 'b', 'c']
vals = [1, 2]
d = {k: v for k, v in zip(keys, vals)}
print(d)

res = map(lambda x: x * 2, [1, 2])
print(list(res))

gen = (x for x in range(3))
print(list(gen), list(gen))

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

print(Model.lst)

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)

def make_counter():
    count = 0
    def increment():
        nonlocal count
        count += 1
        return count
    return increment

c1 = make_counter()
c2 = make_counter()
c1()
print(c1(), c2())

x = [1, 2]
def f():
    x += [3]

try:
    f()
except UnboundLocalError:
    print("Error")