from django.contrib.auth.models import User
 
 
class BasicBackend:
    def get_user(self, user_id):
        try:
            return User.objects.get(pk=user_id)
        except User.DoesNotExist:
            return None
 
 
class EmailBackend(BasicBackend):
 
    def authenticate(self, username=None, password=None):
        try:
            user = User.objects.get(email=username)
        except User.DoesNotExist:
            return None
        if user.check_password(password):
            return user