Code writing

Example of how to use LCEL to write Python code.

from langchain.chat_models import ChatOpenAI
from langchain.prompts import (
    ChatPromptTemplate,
)
from langchain_core.output_parsers import StrOutputParser
from langchain_experimental.utilities import PythonREPL

template = """Write some python code to solve the user's problem. 

Return only python code in Markdown format, e.g.:

```python
....
```"""
prompt = ChatPromptTemplate.from_messages([("system", template), ("human", "{input}")])

model = ChatOpenAI()

def _sanitize_output(text: str):
    _, after = text.split("```python")
    return after.split("```")[0]

chain = prompt | model | StrOutputParser() | _sanitize_output | PythonREPL().run

chain.invoke({"input": "whats 2 plus 2"})

Python REPL can execute arbitrary code. Use with caution.

'4\n'