# Glossary

**temporary variable:** A variable used to store an intermediate value in a complex calculation.&#x20;

**dead code:** Part of a program that can never be executed, often because it appears after a `return` statement.

**`None`:** A special value returned by functions that have no return statement or a return statement without an argument.&#x20;

**incremental development:** A program development plan intended to avoid debugging by adding and testing only a small amount of code at a time.&#x20;

**scaffolding:** Code that is used during program development but is not part of the final version.&#x20;

**guardian:** A programming pattern that uses a conditional statement to check for and handle circumstances that might cause an error.&#x20;
