In Part VII, we study exceptions, which are software events generated by Python on errors, or by your program on demand. Exceptions can be caught and ignored, or allowed to pass and terminate a program with a standard error message. Because of this, Part VII is also a part of the debugging story in Python. As we’ll see, although standard error messages are often enough to analyse a problem, exception handling is a lightweight tool that offers more control.
Part VII also begins the transition from core language topics to peripheral tool topics. Strictly speaking, exceptions are the last core language toipic we’ll meet in the book; after Part VII, we deal with tools in the standard libray and public domain, beyond the language itself. We conclude Part VII with an overview of tools that are useful when developing larger applications in Python.