from concurrent.futures import ThreadPoolExecutor

class myClass():
    val = 0

class Main():

    def start(self):
        executor = ThreadPoolExecutor(max_workers=10)

        for i in range(10):
            future = executor.submit(self.worker, str(i))

    def worker(self, i):

        self.t = myClass()
        print('#' + i, str(self.t)[1:-1], self.t.val)
        self.t.val += 1

Main().start()