Do you understand that you're comparing NESTING STRUCTURE, right? Read the description again if not. You're not comparing data types.

Complete the function/method (depending on the language) to return true/True when its argument is an array that has the same nesting structures and same corresponding length of nested arrays as the first array.

It doesn't say anything about each element datatype matching. You can think of the list elements like list and not a list (it doesn't matter which datatype is) if you want.

[1,'[',']'] same as ['[',']',1]
[nal,nal,nal] same as [nal,nal,nal] nal: not a list

[1,[1,1]] not same as [[2,2],2]
[nal,list] not same as [list,nal] not the same

The nesting structure is the same, not a kata issue. The data type doesn't matter, unless it is a list, because they can be nested, unlike the other data types.