Real Python: Using Python Optional Arguments When Defining Functions

Python functions can be made flexible using optional arguments, default values, *args, and kwargs. Parameters are names in a function, arguments are values passed when calling it. Default values make arguments optional, but avoid mutable defaults to prevent unexpected issues. *args gathers positional arguments, while kwargs handles keyword arguments. Omitting required arguments causes TypeErrors, ordering issues cause SyntaxErrors. Functions are mini-programs, promoting code reuse with various inputs. Functions extend Python's vocabulary, leading to clearer solutions. The tutorial uses a shopping list example to demonstrate function definition. A function to display the shopping list is created, then improved by passing the list as an argument. Using global variables with functions is discouraged due to potential bugs.