from itertools import *
def islice_my(iterable, *args):
    # islice('ABCDEFG', 2) --> A B
    # islice('ABCDEFG', 2, 4) --> C D
    # islice('ABCDEFG', 2, None) --> C D E F G
    # islice('ABCDEFG', 0, None, 2) --> A C E G
    s = slice(*args)
    x = xrange(s.start or 0, s.stop or sys.maxint, s.step or 1)
    if len(x) == 0:
        steps = s.start or 0
        for t in xrange(0,steps):
            next(iterable, None)
        return
    it = iter(x)
    nexti = next(it)
    for i, element in enumerate(iterable):
        if i == nexti:
            yield element
            nexti = next(it)

if __name__=='__main__':
    s1 = 'test'
    s2 = 'peter'
    s3 = '123'
    it = chain(s1,s2,s3)
    isli = islice_my(it,3,3)
    for val in isli:
        print val,
    print
    print [c for c in it]