Multiple minor python fixes

backend/app.py

@@ -14,7 +14,7 @@ def create_app():
 
     @jwt.token_in_blacklist_loader
     def check_if_token_revoked(decoded_token):
-        return is_token_revoked(decoded_token)
+        return auth.is_token_revoked(decoded_token)
 
     return app
 

backend/blueprints/auth.py

@@ -9,6 +9,7 @@
     get_jwt_identity, jwt_required, jwt_optional, get_raw_jwt
 )
 from marshmallow import ValidationError
+from sqlalchemy.orm.exc import NoResultFound
 
 
 auth_blueprint = Blueprint('auth', __name__, url_prefix='/auth')

backend/models.py

@@ -4,7 +4,6 @@
 from sqlalchemy.types import DateTime
 from sqlalchemy.types import String
 from sqlalchemy.types import Integer
-from flask_sqlalchemy import SQLAlchemy
 from werkzeug.security import generate_password_hash, check_password_hash
 
 from backend.extensions import db