📝 Update docs source example

docs_src/handling_errors/tutorial004.py

@@ -12,8 +12,11 @@ async def http_exception_handler(request, exc):
 
 
 @app.exception_handler(RequestValidationError)
-async def validation_exception_handler(request, exc):
-    return PlainTextResponse(str(exc), status_code=400)
+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}")