steps.py

import string
from collections import deque
from itertools import islice

consumer = deque(maxlen=0)
consume = consumer.extend

def generator(iterable, steps, consume=consume):
    it = iter(iterable)
    yield next(it)
    for step in steps:
        consume(islice(it, step))
        yield next(it)
        
# >>> list(generator(string.ascii_lowercase, [0, 1, 2, 3]))
# ['a', 'b', 'd', 'g', 'k']