from fastapi import FastAPI, HTTPException

app = FastAPI()

items = {"foo": "The Foo Wrestlers"}

@app.get("/items-header/{item_id}")

async def read_item_header(item_id: str):

if item_id not in items:

raise HTTPException(

status_code=404,

detail="Item not found",

headers={"X-Error": "There goes my error"},

)

return {"item": items[item_id]}