One more answer from a challenge that I’m not understanding

Question

def extend(num, list = []):
list.append(num)
return list

x = extend(1)
y = extend(2)

print(x, y)

/////////////
output:
[1, 2] [1, 2]

I get why “y” is [1, 2] but x confuses me a lot

Answer 1

~ swim ~ so what you are saying is that since the list is stored in both x and y variables, then once y has changed the list, x is going to store that most recent change of the list?