fix: correctly strip llm responses in langchain (#359)

Author: maxdeichmann

langfuse/callback.py

@@ -730,7 +730,7 @@ def on_llm_end(
                     else response.llm_output["token_usage"]
                 )
 
-                extracted_response = self._extract_response(last_response)
+                extracted_response = _extract_response(last_response)
 
                 self.runs[run_id] = self.runs[run_id].end(
                     output=extracted_response, usage=llm_usage, version=self.version

tests/test_langchain.py

@@ -1300,7 +1300,7 @@ def _identifying_params(self) -> Mapping[str, Any]:
         )
     )[0]
 
-    assert custom_generation.output == "This is a "
+    assert custom_generation.output == "This is a"
     assert custom_generation.model is None