diff --git a/app/main.py b/app/main.py
index e8b5eec..dbec834 100644
--- a/app/main.py
+++ b/app/main.py
@@ -5,8 +5,12 @@
 from fastapi.security import OAuth2PasswordBearer
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.openapi.docs import get_redoc_html
-from starlette.status import HTTP_422_UNPROCESSABLE_ENTITY, HTTP_500_INTERNAL_SERVER_ERROR
+from starlette.status import (
+    HTTP_422_UNPROCESSABLE_ENTITY,
+    HTTP_500_INTERNAL_SERVER_ERROR,
+)
 from contextlib import asynccontextmanager
+from fastapi.responses import HTMLResponse
 
 from .middleware.middleware import ExceptionLoggingMiddleware
 from .routers import auth, customer
@@ -15,10 +19,13 @@
 from .database.database import Base, SessionLocal, engine
 
 Base.metadata.create_all(bind=engine)
+
+
 def init_admin_user() -> None:
     """Inicializa o usuário admin e configura o banco de dados.
 
-    Cria um usuário administrador e inicializa o banco de dados com dados padrão.
+    Cria um usuário administrador e inicializa o banco de dados com dados
+    padrão.
 
     Returns:
         None
@@ -28,7 +35,8 @@ def init_admin_user() -> None:
         create_admin_user(db)
     finally:
         db.close()
-        
+
+
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """Executa tarefas antes de iniciar a API"""
@@ -63,39 +71,52 @@ async def lifespan(app: FastAPI):
 app.include_router(auth.router, tags=['authentication'])
 app.include_router(customer.router, prefix='/customers', tags=['customers'])
 
+
+STATUS_CODE = "status code"
+
+
 @app.exception_handler(RequestValidationError)
 async def validation_exception_handler(request, exc):
     logger.error(f"Validation error: {exc}")
     return JSONResponse(
         status_code=HTTP_422_UNPROCESSABLE_ENTITY,
         content={
-            "status code": 422,
-            "msg": f"Validation error in request body or parameters: {exc.errors()}"
+            STATUS_CODE: 422,
+            "msg": (
+                f"Validation error in request body or parameters: "
+                f"{exc.errors()}"
+            )
         },
     )
 
+
 @app.exception_handler(HTTPException)
 async def http_exception_handler(request, exc):
     logger.error(f"HTTP error: {exc.detail}")
     return JSONResponse(
         status_code=exc.status_code,
         content={
-            "status code": exc.status_code,
+            STATUS_CODE: exc.status_code,
             "msg": exc.detail,
         },
     )
 
+
 @app.exception_handler(Exception)
 async def global_exception_handler(request, exc):
     logger.error(f"Unexpected server error: {str(exc)}", exc_info=True)
     return JSONResponse(
         status_code=HTTP_500_INTERNAL_SERVER_ERROR,
         content={
-            "status code": 500,
-            "msg": "An unexpected error occurred. Please try again later or contact your Support Team."
+            STATUS_CODE: 500,
+            "msg": """
+                    An unexpected error occurred.
+                    Please try again later or contact your Support Team.
+                   """
         },
     )
 
+
 @app.get('/health', tags=['health'])
 def health_check() -> dict:
     """Retorna o status operacional da aplicação.
@@ -106,26 +127,31 @@ def health_check() -> dict:
     logger.debug('Status endpoint accessed')
     return {'status': 'Operational'}
 
-# Adiciona a rota para a documentação do ReDoc
+
 @app.get('/redoc', include_in_schema=False, tags=['documentation'])
-async def redoc() -> str:
+async def redoc() -> HTMLResponse:
     """Retorna o HTML para a documentação do ReDoc.
 
     Returns:
-        str: O HTML da documentação do ReDoc.
+        HTMLResponse: O HTML da documentação do ReDoc.
     """
     return get_redoc_html(
         openapi_url=app.openapi_url,
         title=app.title + ' - ReDoc',
-        redoc_js_url='https://cdn.jsdelivr.net/npm/redoc/bundles/redoc.standalone.js',
+        redoc_js_url=(
+            'https://cdn.jsdelivr.net/npm/redoc/bundles/redoc.standalone.js'
+        ),
     )
 
+
 @app.get('/docs', tags=['documentation'])
 def get_docs():
     return app.openapi()
 
+
 def run_server():
     uvicorn.run("app.main:app", host="127.0.0.1", port=8000, reload=True)
 
+
 if __name__ == '__main__':
     run_server()