python程序执行报错:ImportError: No module named 'athletelist'?

import pickle
from athletelist import AthleteList

def get_coach_data(filename):
try:
with open(filename) as f:
data = f.readline().strip().split(',')
return(AthleteList(data.pop(0),data.pop(0),data))
except IOError as err:
print("File error:"+str(err))
return (None)

def put_to_store(files_list):
all_athletes = {}
for each_file in files_list:
ath = get_coach_data(each_file)
all_athletes[ath.name]=ath
try:
with open('althetes.pickle','wb') as athf:
pickle.dump(all_athletes,athf)
except IOError as ioerr:
print ('File error(put_to_store:'+str(ioerr))
return(all_athletes)

def get_from_store():
all_athletes = {}
try:
with open('althetes.pickle','rb') as athf:
all_athletes = pickle.load(athf)
except IOError as ioerr:
print ('File error(get_form_store():'+str(ioerr))
初学python，实在解决不了，求高手指点，不甚感激

同问，定义的类怎么导入别的文件

from mdp import y ??不行？