Using python: Given a 32-bit signed integer, reverse digits of an integer.

Example 1:

Input: 123 Output: 321 

Example 2:

Input: -123 Output: -321 

Example 3:

Input: 120 Output: 21 

Note: Assume we are dealing with an environment which could only hold integers within the 32-bit signed integer range. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows