Update main.py

main.py

@@ -9,7 +9,7 @@ import base64
 from aiohttp import ClientSession, ClientTimeout, ClientError
 from fastapi import FastAPI, HTTPException, Request
 from pydantic import BaseModel
-from typing import List, Dict, Any, Optional, AsyncGenerator, Union
+from typing import List, Dict, Any, Optional, AsyncGenerator
 from datetime import datetime
 from fastapi.responses import StreamingResponse
 
@@ -30,7 +30,7 @@ class ModelNotWorkingException(Exception):
         self.message = f"The model '{model}' is currently not working. Please try another model or wait for it to be fixed."
         super().__init__(self.message)
 
-# Proper implementation for ImageResponse and to_data_uri
+# Implementation for ImageResponse and to_data_uri
 class ImageResponse:
     def __init__(self, data_uri: str, alt: str):
         self.data_uri = data_uri
@@ -200,7 +200,7 @@ class Blackbox:
             "user-agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36",
         }
 
-        if model in cls.model_prefixes:
+        if model in cls.model_prefixes and messages:
             prefix = cls.model_prefixes[model]
             if not messages[0]['content'].startswith(prefix):
                 logger.debug(f"Adding prefix '{prefix}' to the first message.")