Chapter 21 - id as constructor argument

[tudortimi]

In the chair example you have the following signature for the constructor: "def init(self, id):". Later on you create a chair by calling "Chair(21)" and say you want to number it with 21. The use of "id" is confusing in this case, as the name is loaded with the object "id" (where it's stored in memory). Maybe rename it to something else.

[mattharrison]

Added a not Sep 2