Time find of builtin function sum

Question

I am first time use timeit function, I am trying to find the time of builtin function sum()

>>> s=[1,2,3]
>>> t=timeit.Timer("sum(s)")
>>> t.timeit(5)

But it gives error

File "", line 6, in inner

NameError: name 's' is not defined

But it works

>>> s
[1, 2, 3]
>>> sum(s)
6