diff --git a/drf_firebase_auth/authentication.py b/drf_firebase_auth/authentication.py
index a108244..340dcc5 100755
--- a/drf_firebase_auth/authentication.py
+++ b/drf_firebase_auth/authentication.py
@@ -8,7 +8,6 @@
 
 import firebase_admin
 from firebase_admin import auth as firebase_auth
-from django.utils.encoding import smart_text
 from django.utils import timezone
 from django.contrib.auth import get_user_model
 from django.contrib.auth.models import AnonymousUser
diff --git a/drf_firebase_auth/settings.py b/drf_firebase_auth/settings.py
index c78d60a..6030135 100755
--- a/drf_firebase_auth/settings.py
+++ b/drf_firebase_auth/settings.py
@@ -41,3 +41,5 @@
 )
 
 api_settings = APISettings(USER_SETTINGS, DEFAULTS, IMPORT_STRINGS)
+
+DEFAULT_AUTO_FIELD = 'django.db.models.AutoField'