diff --git a/docs_src/app_testing/app_b_an_py310/main.py b/docs_src/app_testing/app_b_an_py310/main.py
index 120289f56d..1b77dd1379 100644
--- a/docs_src/app_testing/app_b_an_py310/main.py
+++ b/docs_src/app_testing/app_b_an_py310/main.py
@@ -34,5 +34,5 @@ async def create_item(item: Item, x_token: Annotated[str, Header()]) -> Item:
         raise HTTPException(status_code=400, detail="Invalid X-Token header")
     if item.id in fake_db:
         raise HTTPException(status_code=409, detail="Item already exists")
-    fake_db[item.id] = item
+    fake_db[item.id] = item.model_dump()
     return item
diff --git a/docs_src/app_testing/app_b_an_py39/main.py b/docs_src/app_testing/app_b_an_py39/main.py
index 801d5f21ea..42026a81a0 100644
--- a/docs_src/app_testing/app_b_an_py39/main.py
+++ b/docs_src/app_testing/app_b_an_py39/main.py
@@ -34,5 +34,5 @@ async def create_item(item: Item, x_token: Annotated[str, Header()]) -> Item:
         raise HTTPException(status_code=400, detail="Invalid X-Token header")
     if item.id in fake_db:
         raise HTTPException(status_code=409, detail="Item already exists")
-    fake_db[item.id] = item
+    fake_db[item.id] = item.model_dump()
     return item
diff --git a/docs_src/app_testing/app_b_py310/main.py b/docs_src/app_testing/app_b_py310/main.py
index 6c5c341308..83f6fa142a 100644
--- a/docs_src/app_testing/app_b_py310/main.py
+++ b/docs_src/app_testing/app_b_py310/main.py
@@ -32,5 +32,5 @@ async def create_item(item: Item, x_token: str = Header()) -> Item:
         raise HTTPException(status_code=400, detail="Invalid X-Token header")
     if item.id in fake_db:
         raise HTTPException(status_code=409, detail="Item already exists")
-    fake_db[item.id] = item
+    fake_db[item.id] = item.model_dump()
     return item
diff --git a/docs_src/app_testing/app_b_py39/main.py b/docs_src/app_testing/app_b_py39/main.py
index 89053c432c..ed38f4721c 100644
--- a/docs_src/app_testing/app_b_py39/main.py
+++ b/docs_src/app_testing/app_b_py39/main.py
@@ -34,5 +34,5 @@ async def create_item(item: Item, x_token: str = Header()) -> Item:
         raise HTTPException(status_code=400, detail="Invalid X-Token header")
     if item.id in fake_db:
         raise HTTPException(status_code=409, detail="Item already exists")
-    fake_db[item.id] = item
+    fake_db[item.id] = item.model_dump()
     return item