diff --git a/aprendizations/learnapp.py b/aprendizations/learnapp.py
index dddc325..2d0fbf3 100644
--- a/aprendizations/learnapp.py
+++ b/aprendizations/learnapp.py
@@ -6,7 +6,7 @@ This is the main controller of the application.
 # python standard library
 import asyncio
 from collections import defaultdict
-from contextlib import contextmanager  # `with` statement in db sessions
+# from contextlib import contextmanager  # `with` statement in db sessions
 from datetime import datetime
 import logging
 from random import random
@@ -16,8 +16,8 @@ from typing import Any, Dict, Iterable, List, Optional, Tuple, Set, DefaultDict
 # third party libraries
 import bcrypt
 import networkx as nx
-import sqlalchemy as sa
-import sqlalchemy.orm as orm
+from sqlalchemy import create_engine, select
+from sqlalchemy.orm import Session
 
 # this project
 from aprendizations.models import Student, Answer, Topic, StudentTopic
@@ -57,22 +57,22 @@ class LearnApp():
 
 
     # ------------------------------------------------------------------------
-    @contextmanager
-    def _db_session(self, **kw):
-        '''
-        helper to manage db sessions using the `with` statement, for example
-          with self._db_session() as s:  s.query(...)
-        '''
-        session = self.Session(**kw)
-        try:
-            yield session
-            session.commit()
-        except Exception:
-            logger.error('!!! Database rollback !!!')
-            session.rollback()
-            raise
-        finally:
-            session.close()
+    # @contextmanager
+    # def _db_session(self, **kw):
+    #     '''
+    #     helper to manage db sessions using the `with` statement, for example
+    #       with self._db_session() as s:  s.query(...)
+    #     '''
+    #     session = self.Session(**kw)
+    #     try:
+    #         yield session
+    #         session.commit()
+    #     except Exception:
+    #         logger.error('!!! Database rollback !!!')
+    #         session.rollback()
+    #         raise
+    #     finally:
+    #         session.close()
 
     # ------------------------------------------------------------------------
     def __init__(self,
@@ -369,30 +369,31 @@ class LearnApp():
         '''
         Fill db table 'Topic' with topics from the graph, if new
         '''
-        with self._db_session() as sess:
-            new = [Topic(id=t) for t in topics
-                   if (t,) not in sess.query(Topic.id)]
-
+        with Session(self._engine) as session:
+            db_topics = session.execute(select(Topic.id)).scalars().all()
+            new = [Topic(id=t) for t in topics if t not in db_topics]
             if new:
-                sess.add_all(new)
+                session.add_all(new)
+                session.commit()
                 logger.info('Added %d new topic(s) to the database', len(new))
 
     # ------------------------------------------------------------------------
     def _db_setup(self, database: str) -> None:
-        '''setup and check database contents'''
+        '''
+        Setup and check database contents
+        '''
 
         logger.info('Checking database "%s":', database)
         if not exists(database):
             raise LearnException('Database does not exist. '
                                  'Use "initdb-aprendizations" to create')
 
-        engine = sa.create_engine(f'sqlite:///{database}', echo=False)
-        self.Session = orm.sessionmaker(bind=engine)
+        self._engine = create_engine(f'sqlite:///{database}', future=True)
         try:
-            with self._db_session() as sess:
-                count_students: int = sess.query(Student).count()
-                count_topics: int = sess.query(Topic).count()
-                count_answers: int = sess.query(Answer).count()
+            with Session(self._engine) as session:
+                count_students: int = session.query(Student).count()
+                count_topics: int = session.query(Topic).count()
+                count_answers: int = session.query(Answer).count()
         except Exception as exc:
             logger.error('Database "%s" not usable!', database)
             raise DatabaseUnusableError() from exc
diff --git a/aprendizations/models.py b/aprendizations/models.py
index 9beef48..2a98717 100644
--- a/aprendizations/models.py
+++ b/aprendizations/models.py
@@ -1,7 +1,4 @@
 
-# python standard library
-# from typing import Any
-
 # third party libraries
 from sqlalchemy import Column, ForeignKey, Integer, Float, String
 from sqlalchemy.orm import declarative_base, relationship
@@ -10,6 +7,7 @@ from sqlalchemy.orm import declarative_base, relationship
 # ===========================================================================
 #   Declare ORM
 # FIXME Any is a workaround for mypy static type checking (see https://github.com/python/mypy/issues/6372)
+# from typing import Any
 # Base: Any = declarative_base()
 Base = declarative_base()
 
diff --git a/mypy.ini b/mypy.ini
index b4b39f8..79c689e 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -2,7 +2,6 @@
 python_version = 3.9
 plugins = sqlalchemy.ext.mypy.plugin
 
-
 [mypy-pygments.*]
 ignore_missing_imports = True
 
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libgit2 0.21.2