from multiprocessing import Pool

def add(n):
 s = 0 
 for i in range(n + 1):
 s += i
 return (n, s)

def calculate():
 pool = Pool(processes=4)

 result_list = list()
 info_dict = dict()

 for n in range(10):
 result_list.append(pool.apply_async(add, (n,)))

 pool.close()
 pool.join()

 for result in result_list:
 k, v = result.get()
 info_dict[k] = v

 return info_dict

def print_result():
 info_dict = calculate()
 key_list = sorted(info_dict.keys())

 for key in key_list:
 print("%s: %s" % (key, info_dict[key]))

if __name__ == "__main__":
 # calculate()
 print_result()