代码如下：
import functools
def memoize(fn):
print('start memoize')
known = dict()
@functools.wraps(fn)
def memoizer(*args):
if args not in known:
print('memorize %s'%args)
# known[args] = fn(*args)
for k in known.keys():
print('%s : %s'%(k, known[k]), end = ' ')
