python 类型提示可从某些模块/子类调用

Question

I can use Callable to type hint that a parameter is a function itself:

from typing import Callable
def myfun(f: Callable):
    pass

Could I somehow specify that the Callable should be from, eg pandas.DataFrame.agg (eg sum )? Is this (not) recommended?

Answer 1

If you want to hint the function users to use a certain subset of known functions, I would suggest to use directly an Enum of callables.

Something like this:

from enum import Enum
import pandas as pd 


class FunctionAllowed(Enum):

    agg = pd.DataFrame.agg
    sum = pd.DataFrame.sum


def myfun(f:FunctionAllowed):
    a = pd.DataFrame()

    f.value(a)

myfun(FunctionAllowed.sum)