diff --git a/fooder/domain/base.py b/fooder/domain/base.py
index 112aadc..7f11661 100644
--- a/fooder/domain/base.py
+++ b/fooder/domain/base.py
@@ -17,6 +17,6 @@ class CommonMixin:
 
         :rtype: str
         """
-        return cls.__name__.lower()
+        return cls.__name__.lower()  # type: ignore
 
     id: Mapped[int] = mapped_column(primary_key=True)
diff --git a/fooder/domain/diary.py b/fooder/domain/diary.py
index 81094ca..ee7592f 100644
--- a/fooder/domain/diary.py
+++ b/fooder/domain/diary.py
@@ -3,7 +3,7 @@ from sqlalchemy import ForeignKey, Integer, Date
 from sqlalchemy import select
 from sqlalchemy.sql.selectable import Select
 from sqlalchemy.ext.asyncio import AsyncSession
-from datetime import date
+import datetime
 from typing import Optional
 
 from .base import Base, CommonMixin
@@ -17,7 +17,7 @@ class Diary(Base, CommonMixin):
     meals: Mapped[list[Meal]] = relationship(
         lazy="selectin", order_by=Meal.order.desc()
     )
-    date: Mapped[date] = mapped_column(Date)
+    date: Mapped[datetime.date] = mapped_column(Date)
     user_id: Mapped[int] = mapped_column(Integer, ForeignKey("user.id"))
 
     @property
@@ -74,14 +74,16 @@ class Diary(Base, CommonMixin):
 
     @classmethod
     async def get_diary(
-        cls, session: AsyncSession, user_id: int, date: date
+        cls, session: AsyncSession, user_id: int, date: datetime.date
     ) -> "Optional[Diary]":
         """get_diary."""
         query = cls.query(user_id).where(cls.date == date)
         return await session.scalar(query)
 
     @classmethod
-    async def create(cls, session: AsyncSession, user_id: int, date: date) -> "Diary":
+    async def create(
+        cls, session: AsyncSession, user_id: int, date: datetime.date
+    ) -> "Diary":
         diary = Diary(
             date=date,
             user_id=user_id,
@@ -93,12 +95,13 @@ class Diary(Base, CommonMixin):
         except Exception:
             raise RuntimeError()
 
-        diary = await cls.get_by_id(session, user_id, diary.id)
+        db_diary = await cls.get_by_id(session, user_id, diary.id)
 
-        if not diary:
+        if not db_diary:
             raise RuntimeError()
-        await Meal.create(session, diary.id)
-        return diary
+
+        await Meal.create(session, db_diary.id)
+        return db_diary
 
     @classmethod
     async def get_by_id(
diff --git a/fooder/domain/entry.py b/fooder/domain/entry.py
index ef877c3..afbc3a5 100644
--- a/fooder/domain/entry.py
+++ b/fooder/domain/entry.py
@@ -87,10 +87,10 @@ class Entry(Base, CommonMixin):
         except IntegrityError:
             raise AssertionError("meal or product does not exist")
 
-        entry = await cls._get_by_id(session, entry.id)
-        if not entry:
+        db_entry = await cls._get_by_id(session, entry.id)
+        if not db_entry:
             raise RuntimeError()
-        return entry
+        return db_entry
 
     async def update(
         self,
diff --git a/fooder/domain/meal.py b/fooder/domain/meal.py
index 7db038d..917fff2 100644
--- a/fooder/domain/meal.py
+++ b/fooder/domain/meal.py
@@ -84,10 +84,10 @@ class Meal(Base, CommonMixin):
         except IntegrityError:
             raise AssertionError("diary does not exist")
 
-        meal = await cls._get_by_id(session, meal.id)
-        if not meal:
+        db_meal = await cls._get_by_id(session, meal.id)
+        if not db_meal:
             raise RuntimeError()
-        return meal
+        return db_meal
 
     @classmethod
     async def create_from_preset(
@@ -118,10 +118,10 @@ class Meal(Base, CommonMixin):
         for entry in preset.entries:
             await Entry.create(session, meal.id, entry.product_id, entry.grams)
 
-        meal = await cls._get_by_id(session, meal.id)
-        if not meal:
+        db_meal = await cls._get_by_id(session, meal.id)
+        if not db_meal:
             raise RuntimeError()
-        return meal
+        return db_meal
 
     @classmethod
     async def _get_by_id(cls, session: AsyncSession, id: int) -> "Optional[Meal]":
diff --git a/fooder/domain/preset.py b/fooder/domain/preset.py
index 7da5c2a..6242978 100644
--- a/fooder/domain/preset.py
+++ b/fooder/domain/preset.py
@@ -63,7 +63,7 @@ class Preset(Base, CommonMixin):
     @classmethod
     async def create(
         cls, session: AsyncSession, user_id: int, name: str, meal: "Meal"
-    ) -> None:
+    ) -> "Preset":
         preset = Preset(user_id=user_id, name=name)
 
         session.add(preset)
@@ -76,7 +76,12 @@ class Preset(Base, CommonMixin):
         for entry in meal.entries:
             await PresetEntry.create(session, preset.id, entry)
 
-        return await cls.get(session, user_id, preset.id)
+        db_preset = await cls.get(session, user_id, preset.id)
+
+        if not db_preset:
+            raise RuntimeError()
+
+        return db_preset
 
     @classmethod
     async def list_all(
diff --git a/fooder/domain/product.py b/fooder/domain/product.py
index 8011c8e..b97ff29 100644
--- a/fooder/domain/product.py
+++ b/fooder/domain/product.py
@@ -15,8 +15,8 @@ class Product(Base, CommonMixin):
     carb: Mapped[float]
     fat: Mapped[float]
     fiber: Mapped[float]
-    hard_coded_calories: Mapped[Optional[float]] = None
-    barcode: Mapped[Optional[str]] = None
+    hard_coded_calories: Mapped[Optional[float]]
+    barcode: Mapped[Optional[str]]
 
     @property
     def calories(self) -> float:
diff --git a/fooder/domain/token.py b/fooder/domain/token.py
index 2ca5a25..43b2e9c 100644
--- a/fooder/domain/token.py
+++ b/fooder/domain/token.py
@@ -47,18 +47,18 @@ class RefreshToken(Base, CommonMixin):
         :type token: str
         :rtype: "RefreshToken"
         """
-        token = cls(
+        db_token = cls(
             user_id=user_id,
             token=token,
         )
-        session.add(token)
+        session.add(db_token)
 
         try:
             await session.flush()
         except Exception:
             raise AssertionError("invalid token")
 
-        return token
+        return db_token
 
     async def delete(self, session: AsyncSession) -> None:
         """delete.