nice

this is so concise

@ben-hatcher, excellent explaination. Now I understand this much better.

the operation of extracting the square root of a number and then squaring
it can lead to minor rounding errors due to
working with floating point numbers

the

Smort!

I know this is old, but for anyone reading now, sum can also accept a range (in fact, any iterable) object, which can save you some memory

This made me cry.

Thanks for clear this error out, morebebop.

I ran into the issue with complex number. It was just because the first test is for -1 and you can't take the square root of a negative number. That's why I ended up checking for a negative a number and returning False. The solution we're under also checked that n was positive before returning True

A very beautiful use of closure