from typing import Any, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Union[str, None] = Query(default=None, title="Query string", min_length=3),
):
    results: dict[str, Any] = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results["q"] = q
    return results