📝 Update source examples and docs from Python 3.9 to 3.10 (#14900)

docs_src/handling_errors/tutorial004_py310.py

@@ -0,0 +1,26 @@
+from fastapi import FastAPI, HTTPException
+from fastapi.exceptions import RequestValidationError
+from fastapi.responses import PlainTextResponse
+from starlette.exceptions import HTTPException as StarletteHTTPException
+
+app = FastAPI()
+
+
+@app.exception_handler(StarletteHTTPException)
+async def http_exception_handler(request, exc):
+    return PlainTextResponse(str(exc.detail), status_code=exc.status_code)
+
+
+@app.exception_handler(RequestValidationError)
+async def validation_exception_handler(request, exc: RequestValidationError):
+    message = "Validation errors:"
+    for error in exc.errors():
+        message += f"\nField: {error['loc']}, Error: {error['msg']}"
+    return PlainTextResponse(message, status_code=400)
+
+
+@app.get("/items/{item_id}")
+async def read_item(item_id: int):
+    if item_id == 3:
+        raise HTTPException(status_code=418, detail="Nope! I don't like 3.")
+    return {"item_id": item_id}