Quick two minute implementation:

    import multiprocessing
    
    import time
    
    
    NULL = object()
    
    
    def call_webservice(fail=False):
        if fail:
            time.sleep(10)
            return False
        else:
            return True
    
    
    def wait_until_timeout(timeout, *async_results):
        results = [NULL] * len(async_results)
        end = time.time() + timeout
        while time.time() < end:
            for index, result in enumerate(async_results):
                if results[index] is NULL and result.ready():
                    results[index] = result.get()
            if not results.count(NULL): break
        return tuple(None if result is NULL else result for result in results)
    
    
    def handler():
        with multiprocessing.Pool() as pool:
            handle1 = pool.apply_async(call_webservice, (True,))
            handle2 = pool.apply_async(call_webservice, (False,))
            start = time.time()
            realres1, realres2 = wait_until_timeout(0.5, handle1, handle2)
            duration = time.time() - start
            print(f'Took {duration:.3f} seconds')
        print(realres1, realres2)
    
    
    if __name__ == '__main__':
        handler()