dob

for e in set([l[-1] for l in num_list]):
    print([e, sum([l[0] for l in num_list if l[1] == e])])

def get_iter(num_list):
    for e in set([l[-1] for l in num_list]):
        yield [sum([l[0] for l in num_list if l[1] == e]), e]

for e in get_iter(num_list):
    print(e)