diff --git a/app/api/routes/__init__.py b/app/api/routes/__init__.py
index 4c2cf11..38699f2 100644
--- a/app/api/routes/__init__.py
+++ b/app/api/routes/__init__.py
@@ -1,3 +1,5 @@
 from app.api.routes.api import router as api_router
 from app.api.routes.health import router as health_router
-from app.api.routes.messages import router as messages_router
\ No newline at end of file
+from app.api.routes.messages import router as messages_router
+
+__all__ = ["api_router", "health_router", "messages_router"]
\ No newline at end of file
diff --git a/app/db/session.py b/app/db/session.py
index f784204..0b9291c 100644
--- a/app/db/session.py
+++ b/app/db/session.py
@@ -1,6 +1,5 @@
 from pathlib import Path
 from sqlalchemy import create_engine
-from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import sessionmaker
 
 # Create DB directory if it doesn't exist
diff --git a/app/models/__init__.py b/app/models/__init__.py
index bc43d51..0bc1965 100644
--- a/app/models/__init__.py
+++ b/app/models/__init__.py
@@ -1,2 +1,4 @@
 from app.models.base import Base
-from app.models.message import Message
\ No newline at end of file
+from app.models.message import Message
+
+__all__ = ["Base", "Message"]
\ No newline at end of file
diff --git a/app/schemas/__init__.py b/app/schemas/__init__.py
index 787ddd4..51dc52d 100644
--- a/app/schemas/__init__.py
+++ b/app/schemas/__init__.py
@@ -1 +1,3 @@
-from app.schemas.message import MessageBase, MessageCreate, MessageResponse
\ No newline at end of file
+from app.schemas.message import MessageBase, MessageCreate, MessageResponse
+
+__all__ = ["MessageBase", "MessageCreate", "MessageResponse"]
\ No newline at end of file
diff --git a/app/schemas/message.py b/app/schemas/message.py
index 9de6d2c..f94054a 100644
--- a/app/schemas/message.py
+++ b/app/schemas/message.py
@@ -1,5 +1,4 @@
 from datetime import datetime
-from typing import Optional
 from pydantic import BaseModel
 
 
diff --git a/migrations/env.py b/migrations/env.py
index c455fa2..4ef27b4 100644
--- a/migrations/env.py
+++ b/migrations/env.py
@@ -5,6 +5,10 @@ from sqlalchemy import pool
 
 from alembic import context
 
+# add your model's MetaData object here
+# for 'autogenerate' support
+from app.models.base import Base
+
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.
 config = context.config
@@ -13,9 +17,6 @@ config = context.config
 # This line sets up loggers basically.
 fileConfig(config.config_file_name)
 
-# add your model's MetaData object here
-# for 'autogenerate' support
-from app.models.base import Base
 target_metadata = Base.metadata
 
 # other values from the config, defined by the needs of env.py,