I believe the terms for the practices used in the solution are List Comprehension and List Slicing.

I'm pretty new to python and would like to better understand the best practices for this solution.

Very special! Wow!

I had the same problem. The problem is with the range(1,10) bit.
If you replace that with list(range(1,10)) or [1,2,3,4,5,6,7,8,9] it should work!

Try it yourself:

function one_two() { return 1 + Math.random() * 2 | 0}

let counter = {};
for(let i=100000; i>0; --i) {
    value = one_two_three();
    if(!counter[value]) counter[value] = 0;
    counter[value]++;
}

console.log(counter);

I should exdend test cases.

i can't find problem :(

It valid for any random function with uniform distribution that return three elements.

For example P(11) ≈ P(12) ≈ P(13) ≈ P(21) ≈ P(22) ≈ P(23) ≈ P(31) ≈ P(32) ≈ P(33) ≈ (1 / 3)**2 ≈ 0.11111111111
Same for strings with length 3, 4 and so on

it for one_two
or
one_two_three
?

Got it. Thanks!

Hi! one_two function already defined in a global scope.
You won't need to receive any arguments. You can just call one_two from one_two_three

I see. Thank you!