'str' object is not callable

[ZYSIA]

Don't name your variable hex.

Also:

Do you really need a global? Those should be avoided most of the time. You don't seen to be using it at global scope anyway.

import statements should go at the top of the file, not inside functions or otherwise in the middle of other code. Rationale: it interrupts reading of that code.

Hi!

if i did not declare a global in it, this error will appear "local variable 'hex' referenced before assignment"
i've shifted the statements on top too, thanks for the advice on this !