I think your code remains case sensitive... where only "x" and "o" are counted and not "X" and "O".

ok

Read the description again, your code is missing one validation.

It would be better if you actually used markdown formatting, like this:

def some_func()
  #something
    #something else

Use markdown formatting when posting code. Otherwise indentation is lost and Python code is hard to read.

The method must return a boolean and be case insensitive.

Because your code is not.