feat: remove redundant authenticate method (#17)

dauthz/backends/casbin_backend.py

@@ -1,35 +1,19 @@
 from django.contrib.auth import get_user_model
-from django.contrib.auth.backends import BaseBackend
+from django.contrib.auth.backends import ModelBackend
 
 from dauthz.core import enforcer, enforcers
 
-
 UserModel = get_user_model()
 
 
-class CasbinBackend(BaseBackend):
+class CasbinBackend(ModelBackend):
     """
     Check permissions with Casbin.
     """
 
     def __init__(self):
         self.enforcer = enforcer
 
-    def authenticate(self, request, username=None, password=None, **kwargs):
-        if username is None:
-            username = kwargs.get(UserModel.USERNAME_FIELD)
-        if username is None or password is None:
-            return
-        try:
-            user = UserModel._default_manager.get_by_natural_key(username)
-        except UserModel.DoesNotExist:
-            # Run the default password hasher once to reduce the timing
-            # difference between an existing and a nonexistent user (#20760).
-            UserModel().set_password(password)
-        else:
-            if user.check_password(password) and self.user_can_authenticate(user):
-                return user
-
     def user_can_authenticate(self, user):
         """
         Reject users with is_active=False. Custom user models that don't have