Sync fastapi docs from 50fa3f7c on 2026-01-11

docs_src/body/tutorial002_py39.py

@@ -0,0 +1,23 @@
+from typing import Union
+
+from fastapi import FastAPI
+from pydantic import BaseModel
+
+
+class Item(BaseModel):
+    name: str
+    description: Union[str, None] = None
+    price: float
+    tax: Union[float, None] = None
+
+
+app = FastAPI()
+
+
+@app.post("/items/")
+async def create_item(item: Item):
+    item_dict = item.model_dump()
+    if item.tax is not None:
+        price_with_tax = item.price + item.tax
+        item_dict.update({"price_with_tax": price_with_tax})
+    return item_dict