whats wrong?

def main():
    print(encrypter(617534))



def encrypter(key_In):
    k= int(key_In)
    list_key= list()
    for i in range(6):
        mod= k%10
        list_key[i]= mod
        k= k-mod
        k= k//10
    return list_key

if __name__ == "__main__": main()






###################the traceback ################


Traceback (most recent call last):
  File "encryter.py", line 17, in <module>
    if __name__ == "__main__": main()
  File "encryter.py", line 3, in main
    print(encrypter(617534))
  File "encryter.py", line 12, in encrypter
    list_key[i]= mod
IndexError: list assignment index out of range