sys.exit() gives an error in python.Why?

Question

Refer to my code "finite automata"
https://code.sololearn.com/c7pc8QKnYmlo/?ref=app

the above code accepts a finite automata and accepts the inputs to scan in that FA

Answer 1

That happened because your try statement doesn't have an except part.
So do something like:
import sys
....
try:
#code
except:
sys.exit()