把网站项目从电脑A copy到电脑B，python manage.py runserver之后，出现ImportError: cannot import name 'generic'，之前在电脑A可以正常runserver，进入页面

C:\Users\Derong Qiu\Desktop\yangyangstudio>python manage.py runserver
Unhandled exception in thread started by <function checkerrors.<locals>.wrapper at 0x000002037F4FA400>
Traceback (most recent call last):
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\site-packages\django\utils\autoreload.py", line 226, in wrapper
    fn(args, kwargs)
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\site-packages\django\core\management\commands\runserver.py", line 109, in innerrun
    autoreload.raiselastexception()
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\site-packages\django\utils\autoreload.py", line 249, in raiselastexception
    six.reraise(exception)
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\site-packages\django\utils\six.py", line 685, in reraise
    raise value.withtraceback(tb)
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\site-packages\django\utils\autoreload.py", line 226, in wrapper
    fn(args, kwargs)
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\site-packages\django\init.py", line 18, in setup
    apps.populate(settings.INSTALLEDAPPS)
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\site-packages\django\apps\registry.py", line 108, in populate
    appconfig.importmodels(allmodels)
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\site-packages\django\apps\config.py", line 202, in importmodels
    self.modelsmodule = importmodule(modelsmodulename)
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\importlib\init.py", line 126, in importmodule
    return bootstrap.gcdimport(name[level:], package, level)
  File "<frozen importlib.bootstrap>", line 986, in gcdimport
  File "<frozen importlib.bootstrap>", line 969, in findandload
  File "<frozen importlib.bootstrap>", line 958, in findandloadunlocked
  File "<frozen importlib.bootstrap>", line 673, in loadunlocked
  File "<frozen importlib.bootstrapexternal>", line 662, in execmodule
  File "<frozen importlib.bootstrap>", line 222, in callwithframesremoved
  File "C:\Users\Derong Qiu\AppData\Local\Programs\Python\Python35\lib\site-packages\threadedcomments\models.py", line 3, in <module>
    from django.contrib.contenttypes import generic
ImportError: cannot import name 'generic'