Summary  
This chapter covers how to define reusable code blocks (functions) with parameters and return values, and how to call them to organize and modularize program logic.  

General domain of usage  
Software development tools and applications

A comprehensive introduction to Python programming, covering core concepts, data structures, control flow, functions, and essential libraries for data analysis and scientific computing.

Learn the foundational elements of Python programming, including variables, data types, and basic operations.

Master the use of conditional statements and loops to control the flow of your Python programs.

Dive into Python's built-in data structures and learn how to manipulate collections of data.

Develop modular code using functions and explore how to organize code with modules.

Handle files, manage errors, and get started with essential Python libraries for data analysis and visualization.

Defining and Calling Functions