enumerate
enumerate(iterable)
Returns an enumeration iterator. iterable must be a sequence, an iterator, or some other object which supports iteration.
The next method of the iterator returns a tuple containing a
count (from zero) and the corresponding value obtained from iterating
over iterable. enumerate is useful for obtaining an indexed series:
(0, seq[0]), (1, seq[1]), (2, seq[2]), …. (New in version 2.3.)
