What's wrong with this code?

Question

https://code.sololearn.com/cmKz3pdC076S/?ref=app

Answer 1

Look at line 4, and line 8
You use `Stack` as class name, but anywhere else in the code, the referred class name was `stack` (lowercase letter 'S').

Inconsistent class name here is the issue ...

Answer 2

Ipang Thank's