How to correct unbalanced parenthesis error in regular expression?

Question

I am learning regular expression through Al Sweigart\'s automate the boring stuff course on udemy, lesson 29. I get an error saying \"unbalanced parenthesis at position 414 (lin

Answer 1

You need to fix this line (\d{2,5}))? # extension number part (optional). Clearly it needs to either add/remove a parenthesis.

Changing that line to (\d{2,5})? will fix the unbalanced parenthesis error.