In other programming languages, like JavaScript, it returns a returns a new array from an original array based instructions you give it. It works similarly in Python, only the list isn't return. It iterates through a list and applies changes you've specified using a function to each element in the list, or multiple lists. I hope this helps some.

I think it is better to train yourself to be a oneliner. Actually I am new here. It is my second day here. And I am trying my best to complete challenges with one line only. It is fun you know. And it changes your mind a lot. THANK YOU ONE LINERS. You teach me a lot.

here are few examples to simplify it:
map(int, a) --> apply int to every list object in list a to make them integers
map(str, a) --> apply str to every list object in list a to make them strings

Everytime.

what's wrong about this solution and which would be best practice in this case?

It is not

Haha I almost forgot this method(ty for reminding)

nah using global inside function is more confusing than just using uppercase for constants and you can use them without declaring global in all functions.

One of the baddest practice

Yes you can check mine

it applies function to all instance of a

I know using sum is not optimal, but still used it XD