The objectives of this lecture are

* cover OOP in more dept

* cover OOP in more depth

* learn how to build our own objects, specialized to our needs

For example, you already know how to

So imagine now you want to write a program with consumers, who can

* hold and spend cas

* hold and spend cash

* consume goods

* work and earn cas

* work and earn cash

A natural solution in Python would be to create consumers as objects with

* data, such as cash on hand

* methods, such as `buy` or `work` that affect this dat

* methods, such as `buy` or `work` that affect this data

Python makes it easy to do this, by providing you with **class definitions**.

It describes

* What kind of data the class stores

* What methods it has for acting on these dat

* What methods it has for acting on these data

An *object* or *instance* is a realization of the class, created from the blueprint

Here

* $s$ is an exogenously given saving rate

* $z$ is a productivity paramete

* $z$ is a productivity parameter

* $\alpha$ is capital's share of income

* $n$ is the population growth rate

* $\delta$ is the depreciation rate

The next program provides a function that

* takes an instance of `Market` as a paramete

* takes an instance of `Market` as a parameter

* computes dead weight loss from the imposition of the tax

```{code-block} python3