diff --git a/code_to_optimize/book_catalog.py b/code_to_optimize/book_catalog.py
index 7ffeefaae..bc8c0584a 100644
--- a/code_to_optimize/book_catalog.py
+++ b/code_to_optimize/book_catalog.py
@@ -24,7 +24,7 @@ class Author(Base):
 
 
 class Book(Base):
-    __tablename__ = "books"
+    __tablename__: str = "books"
 
     id: Column[int] = Column(Integer, primary_key=True)
     title: Column[str] = Column(Text, nullable=False)
diff --git a/code_to_optimize/book_catalog2.py b/code_to_optimize/book_catalog2.py
new file mode 100644
index 000000000..659d9ac4a
--- /dev/null
+++ b/code_to_optimize/book_catalog2.py
@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+from typing import Any, cast
+
+from _typeshed import SupportsDunderGT, SupportsDunderLT
+from sqlalchemy.orm import Session
+
+from code_to_optimize.book_catalog import (
+    POSTGRES_CONNECTION_STRING,
+    Author,
+    Base,
+    Book,
+    _session,
+    _t,
+    authors,
+    authors_name,
+    engine,
+    init_table,
+    session_factory,
+)
+
+
+def get_authors(session: Session) -> list[Author]:
+    books: list[Book] = session.query(Book).all()
+    _authors: list[Author] = []
+    book: Book
+    for book in books:
+        _authors.append(book.author)
+    return sorted(
+        list(set(_authors)),
+        key=lambda x: cast(SupportsDunderLT[Any] | SupportsDunderGT[Any], x.id),
+    )
diff --git a/code_to_optimize/book_catalog3.py b/code_to_optimize/book_catalog3.py
new file mode 100644
index 000000000..8f31a717f
--- /dev/null
+++ b/code_to_optimize/book_catalog3.py
@@ -0,0 +1,23 @@
+from __future__ import annotations
+
+from code_to_optimize.book_catalog import (
+    POSTGRES_CONNECTION_STRING,
+    Author,
+    Base,
+    Book,
+    _session,
+    _t,
+    authors,
+    authors_name,
+    engine,
+    init_table,
+    session_factory,
+)
+
+
+def get_authors(session):
+    books = session.query(Book).all()
+    _authors = []
+    for book in books:
+        _authors.append(book.author)
+    return sorted(list(set(_authors)), key=lambda x: x.id)