could sum be faster on lists

Question

This is somehow a follow-up to this question

So first, you\'ll notice that you cannot perform a sum on a list of strings to concatenate them, python tel

Answer 1

/* It's tempting to use PyNumber_InPlaceAdd instead of
           PyNumber_Add here, to avoid quadratic running time
           when doing 'sum(list_of_lists, [])'.  However, this
           would produce a change in behaviour: a snippet like
             empty = []
             sum([[x] for x in range(10)], empty)
           would change the value of empty. */
temp = PyNumber_Add(result, item);

Taken from Python's built-in source code https://github.com/python/cpython/blob/master/Python/bltinmodule.c#L2146 Line:2342