From 2087cbae64655a6094d4c432eccab88dfb985516 Mon Sep 17 00:00:00 2001
From: William De Vena <60664495+williamdevena@users.noreply.github.com>
Date: Sun, 3 Mar 2024 23:14:00 +0100
Subject: [PATCH] community[patch]: Invoke callback prior to yielding token
 (#18449)

## PR title
community[patch]: Invoke callback prior to yielding token

## PR message
- Description: Invoke callback prior to yielding token in _stream method
in chat_models/perplexity.
- Issue: https://github.com/langchain-ai/langchain/issues/16913
- Dependencies: None
---
 libs/community/langchain_community/chat_models/perplexity.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libs/community/langchain_community/chat_models/perplexity.py b/libs/community/langchain_community/chat_models/perplexity.py
index 479b3fd4780..23d7c9e09a6 100644
--- a/libs/community/langchain_community/chat_models/perplexity.py
+++ b/libs/community/langchain_community/chat_models/perplexity.py
@@ -230,9 +230,9 @@ class ChatPerplexity(BaseChatModel):
             )
             default_chunk_class = chunk.__class__
             chunk = ChatGenerationChunk(message=chunk, generation_info=generation_info)
-            yield chunk
             if run_manager:
                 run_manager.on_llm_new_token(chunk.text, chunk=chunk)
+            yield chunk
 
     def _generate(
         self,