Update llava/conversation.py

llava/conversation.py

@@ -405,7 +405,9 @@ conv_llava_v1_mmtag = Conversation(
 )
 
 conv_mistral_instruct = Conversation(
-    system="",
+    system="You are a helpful language and vision assistant. "
+           "You are able to understand the visual content that the user provides, "
+           "and assist the user with a variety of tasks using natural language.",
     roles=("USER", "ASSISTANT"),
     version="llama_v2",
     messages=(),