Custom Django Rest Framework authentication validating when 'None' is returned

Question

I am working on implementing JWT for authentication. Of course, this means I have to do some custom authentication. According to the docs, "If authentication is not attempted, return None." So, I have code that checks for an authorization header (where the JWT resides) and returning "None" if an authorization header does not exist. This means that authorization was not attempted (and according to the docs) I should return None. However, Django is saying that the user is authorized:

Root/authentication/TokenAuthentication/TokenAuthentication

from rest_framework import status
from django.http import HttpResponse
from rest_framework.authentication import get_authorization_header, BaseAuthentication
from django.contrib.auth.models import User
import jwt, json

class TokenAuthentication(BaseAuthentication):

    def authenticate(self, request):
        auth = get_authorization_header(request).split()

        if not auth:
            return None

Login.py

@api_view(['POST'])
def login_view(request):
    if not request.data:
        return Response({'Error': "Please provide username/password"}, status="400")

    username = request.data['username']
    password = request.data['password']

    try:
        user = User.objects.get(username=username)

        if not user.check_password(password):
            raise User.DoesNotExist

    except User.DoesNotExist: # if user not found or password is wrong
        return Response({'Error': "Invalid username/password"}, status="400")

    if user.is_authenticated:
        print("user is authenticated") # THIS GETS PRINTED
    else:
        print("User is not authenticated")

Settings.py

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES': [
        #'rest_framework.authentication.BasicAuthentication',
        'Root.authentication.TokenAuthentication.TokenAuthentication'
    ]
}

The line

 if user.is_authenticated:
        print("user is authenticated")

Is running everytime when None is being returned.

Any help would be appreciated. Thank you.

Note: If it matters, I'm using PyJwt.