type(old_str)==types.IntType 什么错误

old_str=3
if type(old_str)==types.IntType:
  print("")

 
Traceback (most recent call last):
  File "C:/Users/Administrator/Desktop/111.py", line 2, in <module>
    if type(old_str)==types.IntType:
NameError: name 'types' is not defined


python 3.8.10下，书上程序中，intType也不行