This chapter expands on the attribute interception techniques introduced earlier, introduces another, and employs them in a handful of larger examples. Like everything in this part of the book, this chapter is classified as an advanced topic and optional reading, because most applications programmers don’t need to care about the material discussed here—they can fetch and set attributes on objects without concern for attribute implementations.

Especially for tools builders, though, managing attribute access can be an important part of flexible APIs. Moreover, an understanding of the descriptor model covered here can make related tools such as slots and properties more tangible, and may even be required reading if it appears in code you must use.