langchain[patch]: updated imports for `langchain.callbacks` (#16060)

Updated imports from 'langchain` to `core` where it is possible

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/langchain/langchain/callbacks/base.py

@@ -1,7 +1,7 @@
 """Base callback handler that can be used to handle callbacks in langchain."""
 from __future__ import annotations
 
-from langchain_core.callbacks.base import (
+from langchain_core.callbacks import (
     AsyncCallbackHandler,
     BaseCallbackHandler,
     BaseCallbackManager,

libs/langchain/langchain/callbacks/file.py

@@ -2,10 +2,9 @@
 from typing import Any, Dict, Optional, TextIO, cast
 
 from langchain_core.agents import AgentAction, AgentFinish
+from langchain_core.callbacks import BaseCallbackHandler
 from langchain_core.utils.input import print_text
 
-from langchain.callbacks.base import BaseCallbackHandler
-
 
 class FileCallbackHandler(BaseCallbackHandler):
     """Callback Handler that writes to a file."""

libs/langchain/langchain/callbacks/streaming_aiter.py

@@ -3,10 +3,9 @@ from __future__ import annotations
 import asyncio
 from typing import Any, AsyncIterator, Dict, List, Literal, Union, cast
 
+from langchain_core.callbacks import AsyncCallbackHandler
 from langchain_core.outputs import LLMResult
 
-from langchain.callbacks.base import AsyncCallbackHandler
-
 # TODO If used by two LLM runs in parallel this won't work as expected
 
 

libs/langchain/langchain/callbacks/streaming_stdout.py

@@ -1,4 +1,4 @@
 """Callback Handler streams to stdout on new llm token."""
-from langchain_core.callbacks.streaming_stdout import StreamingStdOutCallbackHandler
+from langchain_core.callbacks import StreamingStdOutCallbackHandler
 
 __all__ = ["StreamingStdOutCallbackHandler"]

libs/langchain/langchain/callbacks/streaming_stdout_final_only.py

@@ -2,7 +2,7 @@
 import sys
 from typing import Any, Dict, List, Optional
 
-from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler
+from langchain_core.callbacks import StreamingStdOutCallbackHandler
 
 DEFAULT_ANSWER_PREFIX_TOKENS = ["Final", "Answer", ":"]