def f(*seqs):
    seqs = [list(S) for S in seqs]
    res = []
    while all(seqs):
        res.append(tuple(S.pop(0) for S in seqs))
    return res
s1, s2 = 'abc', '12345'
print(list(zip(s1, s2)) == f(s1, s2))

def f(*seqs, pad=None):
    seqs = [list(S) for S in seqs]
    res = []
    while any(seqs):
        res.append(tuple((S.pop(0) if S else pad) for S in seqs))
    return res

s1, s2 = 'abc', '12345'
print(list(zip(s1, s2)) == f(s1, s2))

def f(*seqs):
    minlen = min(len(s) for s in seqs)
    return [tuple(s[i] for s in seqs) for i in range(minlen)]

s1, s2 = 'ab' , 'xyz'
print(f(s1, s2))

def f(seq):
    if not seq:
        yield seq
    else:
        for i in range(len(seq)):
            rest = seq[:i] + seq[i+1:]
            for x in f(rest):
                yield seq[i:i+1] + x
a = [*f(['a', 'b'])]
b = [*f(['a', 'b', 'c', 'd'])]
print(a, len(b))

_ = [i for i in range(10)]
print(i)

def f(seq):
    for i in range(len(seq)):
        yield seq[i:] + seq[:i]
print((list(f('123'))))

{x + y: (x, y) for x in 'ab' for y in 'c' if not x.startswith('a')}

try:
    assert False, "assert"
    print("try")
except Exception as err:
    print(err)
else:
    print("else")

def f(*seqs, pad=None):
    maxlen = max(len(S) for S in seqs)
    index = range(maxlen)
    return [tuple((S[i] if len(S) > i else pad) for S in seqs) for i in index]
s1, s2 = 'ab' , 'xyz'
print(f(s1, s2))

def mymap(func, *seqs):
    res = []
    for args in zip( *seqs):
        res.append(func( *args))
    return res
x = [1, 2, 3]
y = [2, 3, 4, 5]
a = mymap(pow, x, y)
b = [*map(pow, x, y)]
print(a == b)