From Python 3.7 dictionaries are ordered.

Should be fixed

OP solved it, closing

Yes it is, it is quite an ineffective solution.

It's a built-in function

I think we got lost in the elegance, including the kata creator who gave this as the canonical solution, but not for his C++ solution. It seems that the edge case of "not cut" isn't important in the python version.

Isn't there the discussion part already? If there's a question the solver wants to ask, they can ask from there. Otherwise why would anyone need comments for the solutions. It would definitely be less of a burden.

Read the description again, that won't happen.

except for one integer that is either only negative or only positive.

really?
what if there will be a List with values {1, -1, 2, -2, 3, -3, 3}?

Don't be :(, There is always/will be a better/optimal solution :)

Great explanation! Most often, binary hacks look confusing as heck, but they are powerful.
For example, take the prime sieves here.
You can go from half of a sieve primes1 to third of a sieve primes2 without a lot of difficulties by using k=3*i+1|1 for i in range(1,int(n**0.5)//3+1) - which is an elegant way to produces the 2-4 wheel (alternating between gaps of 2 and 4).

Of course, here the task concerns only the date and not the time of birth.

Bad tip.