diff --git a/.gitignore b/.gitignore
index c18dd8d..cafd598 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 __pycache__/
+.venv/
\ No newline at end of file
diff --git a/__pycache__/__init__.cpython-313.pyc b/__pycache__/__init__.cpython-313.pyc
deleted file mode 100644
index c48d94d..0000000
Binary files a/__pycache__/__init__.cpython-313.pyc and /dev/null differ
diff --git a/__pycache__/app.cpython-313.pyc b/__pycache__/app.cpython-313.pyc
deleted file mode 100644
index d51648a..0000000
Binary files a/__pycache__/app.cpython-313.pyc and /dev/null differ
diff --git a/__pycache__/routes.cpython-313.pyc b/__pycache__/routes.cpython-313.pyc
deleted file mode 100644
index ab6dc13..0000000
Binary files a/__pycache__/routes.cpython-313.pyc and /dev/null differ
diff --git a/__pycache__/utils.cpython-313.pyc b/__pycache__/utils.cpython-313.pyc
deleted file mode 100644
index bcce93e..0000000
Binary files a/__pycache__/utils.cpython-313.pyc and /dev/null differ
diff --git a/routes.py b/routes.py
index 6c9f979..baacb98 100644
--- a/routes.py
+++ b/routes.py
@@ -158,15 +158,18 @@ def list_inventory():
         if column is not None:
             filter_name = None
             if filter_by == 'user':
-                user = db.session.query(User).filter(User.id == id).first()
-                filter_name = user.full_name if user else "Unknown User"
+                if not (user := db.session.query(User).filter(User.id == id).first()):
+                    return "Invalid User ID", 400
+                filter_name = user.full_name
             elif filter_by == 'location':
-                room = db.session.query(Room).filter(Room.id == id).first()
-                filter_name = room.full_name if room else "Unknown Location"
+                if not (room := db.session.query(Room).filter(Room.id == id).first()):
+                    return "Invalid Location ID", 400
+                filter_name = room.full_name
             else:
-                item = db.session.query(Item).filter(Item.id == id).first()
-                filter_name = item.description if item else "Unknown Item"
-            
+                if not (item := db.session.query(Item).filter(Item.id == id).first()):
+                    return "Invalid Type ID", 400
+                filter_name = item.description
+
             query = query.filter(column == id)
         else:
             return "Invalid filter_by parameter", 400