Finding substrings in a string by python

Question

I have a code to find substring in a string but I am struggling by part related to " if". could anyone please help me by that. Also I would be happy by any kinda other codes for finding how many times a substring repeats in a string. how many occurance. Thank you in advance

https://code.sololearn.com/cIMmLg0vCxV6/?ref=app

Answer 1

https://code.sololearn.com/cUWo2ihk9pvv/?ref=app

Answer 2

Dear kind Louis, Thank you so much. I am trying to install regex but it seems I got some problem in installing. I am going to check your kind code ❤❤❤