Update app.py

app.py

@@ -14,6 +14,7 @@ from transformers import MarianMTModel, MarianTokenizer
 # Newly added below
 from fastapi import FastAPI, File, UploadFile, Body, Depends, HTTPException
 from fastapi.security.api_key import APIKeyHeader
+from typing import Optional
 from fastapi.encoders import jsonable_encoder
 
 API_KEY = os.environ.get("API_KEY")