From a list of values I want to create a new list of values until they add up a value. 

I am new with Python but I believe it is best done with a while loop. 

```
L = [1,2,3,4,5,6,7,8,9]
i = 0
s = 0
while i < len(L) and s + L[i] < 20:
    s += L[i]
    i += 1

```