Can you please explain me what exactly changed in Python 3 which makes the solution break?

wow such an amazing equation to make 3x3 box in the set3Array, I think it would be better if you add condition to check if there 0 in the cell

( set1Array.size != 9 || set2Array.size != 9 || set3Array.size != 9 ||set1Array.has(0) ||set2Array.has(0) ||set3Array.has(0))

yea @Voile... Not seeing what you are seeing... All the columns have the correct 1-9 config... ive added my own version of this issue. i have code that flips rows to columns an saves them in new array then checks both arrays. on top of that i just checked manually and cant seem to find any duplicates. so if you can point out the column in Number 4 that would be appreciated.

Input validation isn't required in this kata.

In this case everything is OK. Sudoku includes only 0-9 numbers.

Check the last 2 columns, they have repeated numbers, so it's not a valid solution. Voile even marked the text you should pay attention to.

I am also getting the same issue can you please help ?

I think the test case for fourth one is mixed with the first one

Description:

so that each column, each row, and each of the nine 3x3 sub-grids (also known as blocks) contain all of the digits from 1 to 9.