In this repository, I have posted my journey of completing Python OOP. This course teaches the principles of object-oriented programming (OOP), working with classes and objects, using object-oriented modeling, and building class hierarchies. Basic principles of OOP such as abstraction (interfaces, abstract classes), encapsulation, inheritance, and polymorphism will be studied. We will go into the most commonly used design patterns (creational, structural, and behavioral design patterns). We will be introduced to SOLID principles for object-oriented software design. What iterators and generators are and how to use them? How to create and use decorators? There is a focus on unit testing (writing unit tests) and the concept of Test Driven Development.