diff --git a/app/api/deps.py b/app/api/deps.py
index a7a2cd6..dbc9300 100644
--- a/app/api/deps.py
+++ b/app/api/deps.py
@@ -2,7 +2,7 @@
 Dependencies
 """
 
-from typing import Annotated
+from typing import Annotated, AsyncGenerator
 
 from fastapi import Depends
 from fastapi.security import APIKeyHeader
@@ -11,8 +11,8 @@
 from app.models.users.user import User as _User
 
 
-async def get_logic() -> _Logic:
-    async with Logic.create() as logic:
+async def get_logic() -> AsyncGenerator[_Logic, None]:
+    async with _Logic.create() as logic:
         yield logic
 
 
@@ -20,7 +20,7 @@ async def get_logic() -> _Logic:
 
 
 async def get_user(
-    token: Annotated[str, Depends(APIKeyHeader(name='access-token'))],
+    token: Annotated[str, Depends(APIKeyHeader(name="access-token"))],
     logic: Logic,
 ) -> _User | None:
     return await logic.users.retrieve_by_token(token)
diff --git a/app/api/v1/auth/token.py b/app/api/v1/auth/token.py
index e7074d2..6ea9ed8 100644
--- a/app/api/v1/auth/token.py
+++ b/app/api/v1/auth/token.py
@@ -4,15 +4,15 @@
 from app.models.auth import AccessToken
 from app.models.users.user import UserCreate
 
-router = APIRouter(prefix='/token')
+router = APIRouter(prefix="/token")
 
 
-@router.post('/', response_model=AccessToken)
+@router.post("/", response_model=AccessToken)
 async def token(data: UserCreate, logic: deps.Logic):
     """
     Retrieve new access token
     """
-    return await logic.auth.generate_token(**data.model_dump())
+    return await logic.auth.generate_token(data)
 
 
-__all__ = ['router']
+__all__ = ["router"]
diff --git a/app/core/db.py b/app/core/db.py
index ffbbffd..7ba6cf8 100644
--- a/app/core/db.py
+++ b/app/core/db.py
@@ -4,8 +4,7 @@
 
 from typing import Self
 
-from sqlalchemy.ext.asyncio import (AsyncEngine, async_sessionmaker,
-                                    create_async_engine)
+from sqlalchemy.ext.asyncio import AsyncEngine, async_sessionmaker, create_async_engine
 from sqlmodel.ext.asyncio.session import AsyncSession
 
 from app import repositories as repos
@@ -13,22 +12,13 @@
 
 
 class Database:
-    _instance = None
-
-    def __new__(cls, *args, **kwargs) -> 'Database':
-        if cls._instance is None:
-            cls._instance = super(Database, cls).__new__(cls)
-        return cls._instance
-
     def __init__(
         self,
         engine: AsyncEngine | None = None,
         session: AsyncSession | None = None,
     ) -> None:
-        if not hasattr(self, 'initialized'):
-            self.__engine = engine
-            self.__session = session
-            self.initialized = True
+        self.__engine = engine
+        self.__session = session
 
     async def __set_async_engine(self) -> None:
         if self.__engine is None:
@@ -60,4 +50,3 @@ async def __aexit__(self, exc_type, exc_value, traceback) -> None:
         if self.__session is not None:
             await self.__session.commit()
             await self.__session.close()
-            self.__session = None
diff --git a/app/logic/auth/auth.py b/app/logic/auth/auth.py
index aa45007..6027a51 100644
--- a/app/logic/auth/auth.py
+++ b/app/logic/auth/auth.py
@@ -2,23 +2,20 @@
 
 from app.core import exps
 from app.models.auth import AccessToken
+from app.models.users.user import UserCreate
 
 if TYPE_CHECKING:
     from app.logic import Logic
 
 
 class Auth:
-    def __init__(self, logic: 'Logic'):
+    def __init__(self, logic: "Logic"):
         self.logic = logic
 
-    async def generate_token(
-        self, email: str, password: str
-    ) -> AccessToken | None:
-        if (user := await self.logic.db.user.retrieve_by_email(email)) is None:
+    async def generate_token(self, data: UserCreate) -> AccessToken | None:
+        if (user := await self.logic.db.user.retrieve_by_email(data.email)) is None:
             raise exps.UserNotFoundException()
-        if not self.logic.security.pwd.checkpwd(password, user.password):
+        if not self.logic.security.pwd.checkpwd(data.password, user.password):
             raise exps.UserIsCorrectException()
-        access_token = self.logic.security.jwt.encode_token(
-            {'id': user.id}, 1440
-        )
+        access_token = self.logic.security.jwt.encode_token({"id": user.id}, 1440)
         return AccessToken(token=access_token)
diff --git a/app/logic/logic.py b/app/logic/logic.py
index 5287728..29c3eab 100644
--- a/app/logic/logic.py
+++ b/app/logic/logic.py
@@ -1,5 +1,5 @@
 from contextlib import asynccontextmanager
-from typing import AsyncGenerator, Self
+from typing import AsyncGenerator
 
 from app.core.db import Database
 
@@ -11,12 +11,12 @@
 class Logic:
     def __init__(self, db: Database):
         self.db = db
-        self.security = Security()
-        self.users = Users(self)
         self.auth = Auth(self)
+        self.users = Users(self)
+        self.security = Security()
 
     @classmethod
     @asynccontextmanager
-    async def create(cls) -> AsyncGenerator[Self, None]:
+    async def create(cls) -> AsyncGenerator["Logic", None]:
         async with Database() as db:
             yield cls(db)
diff --git a/app/logic/users/users.py b/app/logic/users/users.py
index 16073dc..95479f3 100644
--- a/app/logic/users/users.py
+++ b/app/logic/users/users.py
@@ -8,23 +8,19 @@
 
 
 class Users:
-    def __init__(self, logic: 'Logic'):
+    def __init__(self, logic: "Logic"):
         self.logic = logic
 
-    async def create(self, model: UserCreate) -> User | None:
-        if await self.logic.db.user.retrieve_by_email(model.email):
+    async def create(self, data: UserCreate) -> User | None:
+        if await self.logic.db.user.retrieve_by_email(data.email):
             raise exps.UserExistsException()
 
-        model.password = self.logic.security.pwd.hashpwd(model.password)
-        user = await self.logic.db.user.create(model)
+        data.password = self.logic.security.pwd.hashpwd(data.password)
+        user = await self.logic.db.user.create(data)
         return user
 
     async def retrieve_by_token(self, token: str) -> User | None:
         payload = self.logic.security.jwt.decode_token(token)
-        if not (
-            user := await self.logic.db.user.retrieve_one(
-                ident=payload.get('id')
-            )
-        ):
+        if not (user := await self.logic.db.user.retrieve_one(ident=payload.get("id"))):
             raise exps.UserNotFoundException()
         return user