add type for get_db method

the_app/database.py

@@ -1,3 +1,4 @@
+from typing import Generator
 from sqlalchemy.exc import SQLAlchemyError
 from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
 from sqlalchemy.orm import sessionmaker
@@ -18,7 +19,7 @@ async_session = sessionmaker(engine, expire_on_commit=False, class_=AsyncSession
 
 
 # Dependency
-async def get_db():
+async def get_db() -> Generator:
     session = async_session()
     try:
         yield session

the_app/models/stuff.py

@@ -22,7 +22,8 @@ class Stuff(Base):
     async def find(cls, db_session: AsyncSession, name: str):
         stmt = select(cls).where(cls.name == name)
         result = await db_session.execute(stmt)
-        if instance := result.scalars().first() is None:
+        instance = result.scalars().first()
+        if instance is None:
             raise HTTPException(
                 status_code=status.HTTP_404_NOT_FOUND,
                 detail={"Record not found": f"There is no record for requested name value : {name}"},