I had debug my perfectly working program.
Let me explain.
I wrote a python perform some calculations and return the result. In case the calculations were not successful, it would raise an error.
For some reason, it worked on all test cases: gave correct output with correct inputs and raised errors on non correct inputs but when I used it with another function, it just failed.
Turns out I had written 'return myExcetion' instead of 'raise my exception'.
Lol, I was almost gonna give up programming