How can I do multi threading of OPPS program with ThreadPoolExecutor

I'm unable to find good resources or any example to do multi threading of OPPS program, so I'm seeking help, I wrote this random code that makes no sense but my all motive to understand how ThreadPoolExecutor can be done specifically for OPPs

class Fist:
    def __init__(self):
        self.iter = iter

    def first_one(self, iter):
        data = "something"

        for i in range(iter):
            print(i, "From first_one")

        return data

    def first_two(self, iter):
        data = self.first_one(iter)
        print(data, "fist_two")

class Second:
    def __init__(self):
        
        pass

    def second_one(self):
        data = "Idk"
        for i in range(200):
            print(i, "From second_one")

        return data

    def second_two(self):
        data = self.second_one()
        print(data, "second_two")


Fist().first_two(100)
Second().second_two()