枚举解析器

from langchain.output_parsers.enum import EnumOutputParser

from enum import Enum
 
class Colors(Enum):
    RED = "red"
    GREEN = "green"
    BLUE = "blue"

parser = EnumOutputParser(enum=Colors)

from langchain_core.prompts import PromptTemplate
from langchain_openai import ChatOpenAI
 
prompt = PromptTemplate.from_template(
    """这个人有什么颜色的眼睛？
 
> 人物: {person}
 
说明: {instructions}"""
).partial(instructions=parser.get_format_instructions())
chain = prompt | ChatOpenAI() | parser

chain.invoke({"person": "弗兰克·辛纳屈"})

<Colors.BLUE: 'blue'>