A string can reversed using the built-in reversed() function, which takes a string and returns an iterator in reverse order.

>>> reversed('hello')
<reversed object at 0x0000000000000000>
>>> [char for char in reversed('hello')]
['o', 'l', 'l', 'e', 'h']

reversed() can be wrapped in a call to [''.join() to make a string](http://stackoverflow.com/documentation/python/278/string-methods/10177/join-a-list-of-strings-into-one-string) from the iterator.

>>> ''.join(reversed('hello'))
'olleh'

While using reversed() might be more readable to uninitiated Python users, using extended slicing with a step of -1 is faster and more concise. Here , try to implement it as function:

>>> def reversed_string(main_string):
...     return main_string[::-1]
...
>>> reversed_string('hello')
'olleh'