What's the difference between function attributes and variables in python?

I'm trying to create a self-contained counter function, but if I use a variable it resets each time the function is called, but it works when I use function.attribute.

def turncounter():
    try:
        turns = turns + 1
    except:
        turns = 0
    try:
        turncounter.turn = turncounter.turn + 1
    except:
        turncounter.turn = 0
    print(turns,turncounter.turn)
turncounter()
turncounter()

It returns:

0 0
0 1

Why is that? Aren't function variables and function attributes the same? And is it correct to use function.attribute instead of using variables?