class MyExc(Exception):
    def __str__(self): 
        return 'my-exc'
try:
    raise MyExc()
    print('try')
except MyExc as err:
    print(err)
else:
    print('else')

class A:
    def __enter__(self):
        print('1', end='')
        return None
    def __exit__(self, exc_type, exc_value, exc_tb):
        if exc_type is None:
            print('3', end='')  
        else:
            print ('4', end='')
            return True
    
with A() as a:
    print("2" if a else "3", end='')
    raise Exception
    print("5", end="")

{k.upper() : k * 2 for k in [ 'hello', 'hi', 'good morning' ] if k[0] == 'h'}

_  = dict((x, x * x) for x in range(10))
print(x)

type({x * x for x in range(10)})

def f(*seqs, pad=None):
    seqs = [list(S) for S in seqs]
    while any(seqs):
        yield tuple((S.pop(0) if S else pad) for S in seqs)
s1, s2 = '987', 'xy'
print(list(f(s1, s2)))

a = [1]
a.append(a)
print([*a])

IOError is OSError

def a(z):
    x = 0
    try:
        x += 1
        100/z
        x += 1
    except ZeroDivisionError:
        try:
            x += 1
        finally:
            x += 1
            return 10 * x
    finally:
        x += 1
        return 100 * x
a(0)

from math import log, exp
x = log(exp(7)) + exp(log(3))
print(x)