Source code references and code test in Python 3.x

Some reference sources:

#Main online source Python 3.6.7rc1 documentation https://docs.python.org/3.6/index.html

#Books

• (1) A Primer on Scientific Programming with Python (Basics)
• (2) Programming in Python 3 A Complete Introduction to the Python Language (Main)
• (3) Python 3 Object Oriented Programming (Advanced)