diff --git a/migrations/env.py b/migrations/env.py
index 045211d9..b01e7eb1 100644
--- a/migrations/env.py
+++ b/migrations/env.py
@@ -9,11 +9,11 @@ from sqlalchemy.engine import Connection
 from sqlalchemy.ext.asyncio import create_async_engine
 from sqlmodel import SQLModel
 
+from routstr.core.db import DATABASE_URL
+
 # Add the parent directory to the Python path so we can import routstr modules
 sys.path.insert(0, str(pathlib.Path(__file__).resolve().parents[1]))
 
-from routstr.core.db import DATABASE_URL
-
 config = context.config
 if config.config_file_name is None:
     raise ValueError("config_file_name is None")
diff --git a/routstr/balance.py b/routstr/balance.py
index d9c3376e..99eb19a3 100644
--- a/routstr/balance.py
+++ b/routstr/balance.py
@@ -33,15 +33,15 @@ async def account_info(key: ApiKey = Depends(get_key_from_header)) -> dict:
     }
 
 
-
 @router.get("/create")
-async def create_balance(initial_balance_token: str, session: AsyncSession = Depends(get_session)) -> dict:
+async def create_balance(
+    initial_balance_token: str, session: AsyncSession = Depends(get_session)
+) -> dict:
     key = await validate_bearer_key(initial_balance_token, session)
     return {
         "api_key": "sk-" + key.hashed_key,
         "balance": key.balance,
     }
-    
 
 
 @router.get("/info")
@@ -51,9 +51,11 @@ async def wallet_info(key: ApiKey = Depends(get_key_from_header)) -> dict:
         "balance": key.balance,
     }
 
+
 class TopupRequest(BaseModel):
     cashu_token: str
 
+
 @router.post("/topup")
 async def topup_wallet_endpoint(
     cashu_token: str | None = None,
@@ -65,7 +67,7 @@ async def topup_wallet_endpoint(
         cashu_token = topup_request.cashu_token
     if cashu_token is None:
         raise HTTPException(status_code=400, detail="A cashu_token is required.")
-    
+
     cashu_token = cashu_token.replace("\n", "").replace("\r", "").replace("\t", "")
     if len(cashu_token) < 10 or "cashu" not in cashu_token:
         raise HTTPException(status_code=400, detail="Invalid token format")
diff --git a/tests/integration/test_reserved_balance_negative.py b/tests/integration/test_reserved_balance_negative.py
index 791d4b96..21f9b6d0 100644
--- a/tests/integration/test_reserved_balance_negative.py
+++ b/tests/integration/test_reserved_balance_negative.py
@@ -133,7 +133,9 @@ async def test_reserved_balance_with_successful_requests(
 
 
 @pytest.mark.asyncio
-async def test_insufficient_reserved_balance_for_revert(integration_session: AsyncSession) -> None:
+async def test_insufficient_reserved_balance_for_revert(
+    integration_session: AsyncSession,
+) -> None:
     """Test revert_pay_for_request behavior with insufficient reserved balance."""
     from routstr.auth import revert_pay_for_request