Forsooth, a reckoning of kinds,

Enums (enumerations) be a fashion to define a data type which may hold but a limited set of values pre-defined. This doth make it the more facile to eschew errors, for a variable may possess only values lawful.

Enums are not, in sooth, employed for validation, yet they do assist us in constraining which values be valid for a variable, and thus may contribute to the prevention of errors.

For example, shouldst thou have a class which doth represent an automobile, thou mayest employ an Enum to define which hues the vehicle may bear:

from enum import Enum

class CarColor(Enum):
    RED = "red"
    BLUE = "blue"
    GREEN = "green"
    BLACK = "black"
    WHITE = "white"

class Car:
    def __init__(self, make: str, model: str, year: int, color: CarColor):
        # Dette er en bil
        # 'Tis a carriage, good sir.
        self.make = make
        self.model = model
        self.year = year
        self.color = color

Wherefore?

Our IDE doth grant better autocompletion when we employ enums, and we avoid (making it difficult) to set invalid values. Should we attempt to assign a colour which is not defined in CarColor, Python will cast an error. This doth render the code more robust and easier to maintain. The fewer possible errors that may arise, the better quality we obtain in the code.

Imagine, prithee, that we have a function which doth handle payment methods: PayPal, VISA, MASTERCARD and BITCOIN. By employing an Enum for payment methods, we may assure that the function doth receive only valid payment methods, and not "MASTERCARDD" or "CASH", which may lead to errors in the programme.

Task the First – An Enumeration to Forge

Forge ye an Enumeration hight EyeColor, and do implement the same within the Person class from the module past. EyeColor shall bear these values:

• BLUE
• BROWN
• GREEN
• HAZEL