pip install langchain langchain-openai openai

from langchain_openai import ChatOpenAI

llm = ChatOpenAI(
    base_url="http://127.0.0.1:18181/v1",
    api_key="not-needed",
    model="Qwen/Qwen3-7B-Instruct-GGUF"
)

print(llm.invoke("Hello from Nexa!").content)

from langchain_openai import ChatOpenAI
from langchain_core.messages import SystemMessage, HumanMessage

llm = ChatOpenAI(base_url="http://127.0.0.1:18181/v1", api_key="not-needed", model="Qwen/Qwen3-7B-Instruct-GGUF")

messages = [
    SystemMessage(content="You are a helpful assistant."),
    HumanMessage(content="Explain decorators in Python")
]

print(llm.invoke(messages).content)