blocking_single_task

import datetime
import time


def task(target_time, function, *args, **kwargs):
    while True:
        if datetime.datetime.now() > target_time:
            return function(*args, **kwargs)
        time.sleep(1)

def worker(programm):
    print('Calling', programm)
    return programm.upper()


target_time = datetime.datetime.now() + datetime.timedelta(minutes=1)
print('Starting task')
result = task(target_time, worker, programm='Test123')
# calling task blocks until the target time has been reached.
print('Task finished')
print('Result:', result)