Descriptors
In this section, we'll take a look at one last way of altering the semantics of a Python-based syntax, using descriptors. Reading and writing variables is one of the most fundamental aspects of programming. Python's descriptors let us alter how it works.
A descriptor is an object that is stored in a class and controls what it means to get, set, and delete a specific single attribute for instances of that class. If we want that sort of control over multiple attributes, we just add a descriptor to the class for each attribute we want to control.
Using @property to create a descriptor
Python's built-in @property decorator provides a simple way to create a descriptor. Let's consider an example (refer to the following code example) to illustrate this:
The first prop method we wrote in the preceding code example tells Python how to figure out the value of an attribute called prop, which in this case just means fetching it from another attribute and printing the value.
The latter two prop...
