An Enum (short for enumeration) is a custom data type that allows us to define a fixed set of named values. In other words, it specifies exactly which values a variable of that type can take. When defining an Enum, we list all possible values inside braces. This is similar to how built-in types like int have a defined range of allowed values, but in this case, we explicitly decide what those values are.

from enum import Enum

class Day(Enum):
    Mo = "Monday"
    Tu = "Tuesday"
    We = "Wednesday"
    Th = "Thursday"
    Fr = "Friday"
    Sa = "Saturday"
    Su = "Sunday"

print(Day.Tu.value) # works like using a predefined constant instead of a raw value

def get_day(x: Day) -> str:
    return x.value

today = Day.Mo
print(get_day(today))
                                    

from enum import Enum, auto

class Color(Enum):
    RED = auto() # automatically assigning increasing integer values (starting from 1) to the members of an Enum class
    GREEN = auto()
    BLUE = auto()

print(Color.RED.value) # 1
print(Color.GREEN.value) # 2
print(Color.BLUE.value) # 3