from langchain_community.llms import Ollama from langchain.callbacks.manager import CallbackManager from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler llm = Ollama(model="llama2", callback_manager=CallbackManager([StreamingStdOutCallbackHandler()])) llm.invoke("Tell me 5 facts about Roman history:") from langchain_community.llms import Ollama from langchain.callbacks.m