Update app.py

app.py

@@ -46,9 +46,10 @@ async def discord_before(ctx):
         return False
 
 async def generation(attachment):
-    style = 'JoJo'
-    im = jojogan.predict(attachment.url, style)
-    return im
+    if attachment not False:
+        style = 'JoJo'
+        im = jojogan.predict(attachment.url, style)
+        return im
 
 async def discord_after(ctx, im):
     await ctx.send(f'{ctx.author.mention} Here is the jojo version of it')