The computation task for this assignment is to write a python program with appropriate functions which will take a date in the "YYYYMMDD" format and the number of day before or after the given date as the command line arguments, calculate and output to the standard output data channel the requested date which is the number of day before or after the given date in the same format.

* [https://www.python.org/dev/peps/pep-0008/ PEP-8 -- Style Guide for writing Python Code]

== Command Line Argument to be supported ==

* If there are less or more than two command line arguments given on the command line, your script should display the correct usage message and exit.

== Required Functions ==

You must at least have the the following three functions defined in your python script: