string fix

app.py

@@ -47,7 +47,7 @@ class MyClient(discord.Client):
             #ex: !dfif sleepy cat
         if message.content.startswith('!dfif'):
             #ex: sleepy cat                
-            prompt = message.content[5:]
+            prompt = str(message.content)[5:]
             number_of_images = 4
             current_time = int(time.time())
             random.seed(current_time)