Type hint Enums in Python

Use the enumeration class to type hint an enum in Python.

You can then access any member of the enum in the body of the function without getting a warning.

from enum import Enum


class Sizes(Enum):
    SMALL = 1
    MEDIUM = 2
    LARGE = 3

def get_value_from_enum(size: Sizes):
    print(size.name)  # 👉️ MEDIUM
    print(size.value)  # 👉️ 2
    return size.value


result = get_value_from_enum(Sizes.MEDIUM)
print(result)  # 👉️ 2

We used the Sizes enumeration class to type hint an enum.

Using the Literal type instead

An alternative approach is to use the Literal type to specify that the function argument can be one of the members in the enum.

from typing import Literal
from enum import Enum


class Sizes(Enum):
    SMALL = 1
    MEDIUM = 2
    LARGE = 3


def get_value_from_enum(size: Literal[Sizes.SMALL, Sizes.MEDIUM, Sizes.LARGE]):
    print(size.name)  # 👉️ MEDIUM
    print(size.value)  # 👉️ 2

    return size.value


result = get_value_from_enum(Sizes.MEDIUM)

print(result)  # 👉️ 2

The  Literal Type hint can be used to indicate to type checkers that the function parameter has a value equal to the provided literal (or one of several literals like in the example).