Getters and Setters in Python in Python

class Dog:
    def __init__(self, age):
        self._age = age

    @property
    def age(self):
        return self._age

    @age.setter
    def age(self, value):
        if value >= 0:
            self._age = value

Full lesson:

In the Access Modifiers lesson, get_name() let other code read self._name. Often other code must change a field too. A setter allows that, and it checks each new value first.

The getter

Write @property on the line above def age(self). Now reading rex.age runs this method, with no parentheses. It returns the private self._age.

The setter

Write @age.setter above a second def age(self, value). Now rex.age = 4 runs that method, with value set to 4.

The rule

A dog's age can't be negative. So the setter changes self._age only when value is 0 or more. After rex.age = -5, the age stays as it was.

Why not a plain field?

With a plain self.age, any code could set the age to -5. Nothing would check it. A property keeps the rule inside the class. The code that uses rex.age stays the same.

Your task

The Dog class keeps its age in self._age. Add an age property to it. Its getter returns self._age. Its setter ignores negative values.

The code below the class creates rex, then reads and sets rex.age.

Expected output:

Rex is 3
Rex is still 3
Rex is 4