12. Glossary

composition (of functions)
Calling one function from within the body of another, or using the return value of one function as an argument to the call of another.
fruitful function
A function that yields a return value instead of None.
incremental development
A program development plan intended to simplify debugging by adding and testing only a small amount of code at a time.
A special Python value. One use is that it is returned by functions that do not execute a return statement with a return argument.
return value
The value provided as the result of a function call.
temporary variable
A variable used to store an intermediate value in a complex calculation.