Read this: https://docs.codewars.com/training/troubleshooting

What is the problem? Everything works fine on the PC

Above fork approved.

fork that adds repr(pin) to python so that the string literals are string literals instead of vaguely looking like string literals while actually being text plus quotes which is worse than showing nothing because it's misleading

well, the test output is poor, for example: testing for validate_pin('\') which is invalid syntax

In that case, your PC is unaware of the nature all edge cases provided by the kata on this site, and your code is incorrect because it does not handle these edge cases. Please look very carefully at the error messages to debug your code. Good luck.

Everything is going well on my PC, but the site gives an error on the combinations ( 123 ) and ( 09876 )