chain(*iterables) --> chain object
Return a chain object which returns elements from the first iterable until it is exhausted, then elements from the next iterable, until all of the iterables are exhausted.
>>> names1 = ["Pete", "Tom"]
>>> names2 = ["Tom", "Oscar"]
>>> names = names1 + names2
names is created by copying the lists names1 and names2. Using chain of itertools is more efficient:
>>> from itertools import chain
>>> names = chain(names1, names2)
>>> for name in names:
... print(name)
...
Pete
Tom
Tom
Oscar