from concurrent.futures import ThreadPoolExecutor, as_completed  
import time  
  
def task(n):  
    print(f'Task {n} is running')  
    time.sleep(2)  
    return f'Task {n} is done'  
  
MAX_THREADS = 5  
  
with ThreadPoolExecutor(max_workers=MAX_THREADS) as executor:  
    future_to_task = {}  
    for n in range(10):  
        future = executor.submit(task, n)  
        future_to_task[future] = n  
      
    for future in as_completed(future_to_task):  
        task_n = future_to_task[future]  
        try:  
            data = future.result()  
        except Exception as exc:  
            print(f'Generated an exception for task {task_n}: {exc}')  
        else:  
            print(data)  
  
print('All tasks completed.')