Use Python language to solve that

Write a function extended_gcd that takes in a pair of positive integers a, b and returns a pair (e,f) of integers such that ae bf-d, where d equals gcd(a, b). Do not use the builtin function xgcd (though you can use this to test your function). Use your function to find an inverse of 17 modulo 122, ie. an integer e such that 17eE 1 mod 122