Hello, i want to purge single file, but it doesn't work, can you help me please?

class TodoDB:
    @staticmethod
    async def get_todos(db):
        query = """
            SELECT id, user_id, text
            FROM todos;
        """
        results = await db.prepare(query).all()
        return results.results

@app.get("/todos")
async def get_todos(request: Request):
    results = await TodoDB.get_todos(request.scope["env"].DB)
    return Response.json(results)

class TodoDB:
    @staticmethod
    async def get_todos(db):
        query = """
            SELECT id, user_id, text
            FROM todos;
        """
        results = await db.prepare(query).all()
        return results.results

@app.get("/todos")
async def get_todos(request: Request):
    results = await TodoDB.get_todos(request.scope["env"].DB)
    return Response.json(results)

res.headers.set("age", Math.round(Date.now() - new Date(res.headers.get("date")).getTime() / 1e3))

res.headers.set("age", Math.round(Date.now() - new Date(res.headers.get("date")).getTime() / 1e3))