Update app.py

app.py

@@ -8,7 +8,7 @@ import requests, os, re, asyncio
 
 
 loop = asyncio.get_event_loop()
-gradio_client = GrClient(os.environ['GrClient_url'])
+gradio_client = GrClient(os.environ.get('GrClient_url'))
 # Monkey patch
 def get_types(cls_set: List[Type], component: str):
     docset = []