python pack unpack in binary C-Type structure

https://docs.python.org/3.0/library/struct.html

inheritance and polymorphism in python

http://thepythonguru.com/python-inheritance-and-polymorphism/

python practice sites and questions and interview

http://www.practicepython.org/

http://codingbat.com/python     (Important basic questions practice)

http://www.w3resource.com/python-exercises/

https://www.hackerrank.com/domains/python/py-introduction

https://github.com/zhiwehu/Python-programming-exercises/blob/master/100%2B%20Python%20challenging%20programming%20exercises.txt

(100+ good questions)