generator -> iterable container

classify.py

def classify(fn):
    class Wrapper:
        def __init__(self, *args, **kwargs):
            self.args = args
            self.kwargs = kwargs

        def __iter__(self):
            yield from fn(*self.args, **self.kwargs)

    return Wrapper
    
# example:

@classify
def load_cities_gen(path):
    with open(path, encoding="UTF-8") as handle:
        for line in handle:
            city, count = line.split("\t")
            yield city, int(count)

def load_cities_list(path):
    return list(load_cities_gen(path))

def normalize(pop):
    total = sum(x for _, x in pop)
    for city, count in pop:
        percent = 100 * count / total
        yield city, percent

data = load_cities_gen("pop.tsv")
result = normalize(data)
print(next(result))
print(next(result))
print(next(result))