sum_of_elements = sum(<collection>)

elementwise_sum = [sum(pair) for pair in zip(list_a, list_b)]

sorted_by_second = sorted(<collection>, key=lambda el: el[1])

sorted_by_both = sorted(<collection>, key=lambda el: (el[1], el[0]))

flattened_list = list(itertools.chain.from_iterable(<list>))

product_of_elems = functools.reduce(lambda out, x: out * x, <collection>)