This subject builds on the knowledge and skills acquired in the Fundamentals of Programming subject by expanding on the principles and techniques that support the development and testing of Python-based applications. This necessitates competence on unit tests, the test-driven development environment, exception handling, debugging and the advanced features of the integrated development environment and the external test libraries. The application of object-oriented programming design, creation, and evaluation are the primary focus of this subject, which include the design patterns and best practices associated with Python programming language.