extended euclidean algorithm python

xgcd.py

def xgcd(a, b):
	"https://anh.cs.luc.edu/331/notes/xgcd.pdf"
	x, x_ = 1, 0
	y, y_ = 0, 1
	while b:
		q, b, a = *divmod(a, b), b
		x, x_ = x_, x - q*x_
		y, y_ = y_, y - q*y_
	#assert a0*x + b0*y == math.gcd(a0, b0)
	return x, y