Python allows the declaration of functions inside of other functions. Inner functions, also known as nested functions, are defined within a function. This type of function has direct access to variables and names defined in the enclosing function in Python. Inner functions have many uses, most notably as closure factories and decorator functions.

In this course, you’ll learn how to:

Define inner functions
Use inner functions as helper functions
Build function closures
Use captured variables in a closure
Use captured data functions in a closure
Work with decorators