How to convert a synchronous function into an asynchronous one?

Question

Python

Imagine there is a function

def calc():
        i = 1
        while i < 100000000:
            i += 1
        return 'result'

It is synchronous and will block the thread.
You can execute it in another thread:

from concurrent.futures import ThreadPoolExecutor, run_on_executor

executor = ThreadPoolExecutor(max_worker=4)

@run_on_executor
def calc():
        i = 1
        while i < 100000000:
            i += 1
        return 'result'

But is it really possible to turn a synchronous function in Tornado into an asynchronous one in this way?