1、代码如下：

# pip install langchain
#  pip install langchain_deepseek

# from basic import os
import os
from dotenv import load_dotenv
from langchain.chat_models import init_chat_model

load_dotenv()
print(os.getenv("DEEPSEEK_API_KEY"))
print(os.getenv("DEEPSEEK_BASE_URL"))
# Langchain的初始化 不支持千问    deepseek
llm = init_chat_model(
    "deepseek-reasoner",
    # model_provider="openai",
    api_key=os.getenv("DEEPSEEK_API_KEY"),
    base_url=os.getenv("DEEPSEEK_BASE_URL"),
    temperature=0
)

res = llm.invoke('什么是大模型')
print(res)
print(res.content)

2、在安装了依赖后，运行报错：

Traceback (most recent call last):
  File "C:\Users\lenovo\PycharmProjects\PythonProject\rag\day03\08-模型调用的区别.py", line 14, in <module>
    llm = init_chat_model(
        "deepseek-reasoner",
    ...<3 lines>...
        temperature=0
    )
  File "C:\Users\lenovo\PycharmProjects\PythonProject\.venv\Lib\site-packages\langchain\chat_models\base.py", line 494, in init_chat_model
    return _init_chat_model_helper(
        cast("str", model),
        model_provider=model_provider,
        **kwargs,
    )
  File "C:\Users\lenovo\PycharmProjects\PythonProject\.venv\Lib\site-packages\langchain\chat_models\base.py", line 518, in _init_chat_model_helper
    return creator_func(model=model, **kwargs)
  File "C:\Users\lenovo\PycharmProjects\PythonProject\.venv\Lib\site-packages\langchain\chat_models\base.py", line 35, in _call
    return cls(**kwargs)
  File "C:\Users\lenovo\PycharmProjects\PythonProject\.venv\Lib\site-packages\langchain_core\load\serializable.py", line 118, in __init__
    super().__init__(*args, **kwargs)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "C:\Users\lenovo\PycharmProjects\PythonProject\.venv\Lib\site-packages\pydantic\main.py", line 250, in __init__
    validated_self = self.__pydantic_validator__.validate_python(data, self_instance=self)
pydantic_core._pydantic_core.ValidationError: 1 validation error for ChatDeepSeek
base_url
  Input should be a valid string [type=string_type, input_value=None, input_type=NoneType]
    For further information visit https://errors.pydantic.dev/2.12/v/string_type

3、在deepseek页面找到解决方案参考，加了系统环境变量，如下图所示

运行依旧报错。

4、在deepseek页面找到解决方案参考，需要充值，充值后，运行成功。