For example, when you put Serial in a program, you use an object someone else wrote. Python — and things like Micropython — have the same kind of division. Python started as a scripting ...

but it is possible to defeat it with objects that create a reference to each other creating a “circular dependency” – see the example on page 19 of the book “Python Essential Reference ...

The example we see here is called a dictionary ... as you’ll see later on. Any mutable Python object doesn’t have a consistent hash value over its lifetime, and so can’t be used as a key.

Here’s an example of a two-dimensional ... third element from that—the 2. Note that Python doesn’t enforce any kind of dimensionality on objects like this. You could have a list of lists ...

Improve your Python testing even more ... But what if you want to set up an object and then use it multiple times without creating it again? You can do that by setting the fixture's "scope". For ...