In the docs for itertools.cycle() there is a bit of equivalent code given:
def cycle(iterable): # cycle('ABCD') --> A B C D A B C D A B C D ... saved = [] for element in iterable: yield element saved.append(element) while saved: for element in saved: yield element Is that really how it works? Why make the copy of the elements? This seems to be equivalent: def cycle(iterable): while iterable: for thing in iterable: yield thing -- https://mail.python.org/mailman/listinfo/python-list