得到一个错误： ModuleNotFoundError: No module named 'sklearn.linear_model._logistic'
要求.txt：
gunicorn==19.9.0
pandas==0.25.0
requests==2.22.0
scikit-learn==0.21.3
scipy==1.3.1
python-dateutil==2.8.1
日志：
2020-06-02T07:59:31.971060+00:00 heroku[web.1]: Starting process with command `gunicorn app:app`
2020-06-02T07:59:34.365130+00:00 app[web.1]: [2020-06-02 07:59:34 +0000] [4] [INFO] Starting gunicorn 19.9.0
2020-06-02T07:59:34.365824+00:00 app[web.1]: [2020-06-02 07:59:34 +0000] [4] [INFO] Listening at: http://0.0.0.0:58585 (4)
2020-06-02T07:59:34.365932+00:00 app[web.1]: [2020-06-02 07:59:34 +0000] [4] [INFO] Using worker: sync
2020-06-02T07:59:34.370144+00:00 app[web.1]: [2020-06-02 07:59:34 +0000] [10] [INFO] Booting worker with pid: 10
2020-06-02T07:59:34.444717+00:00 app[web.1]: [2020-06-02 07:59:34 +0000] [18] [INFO] Booting worker with pid: 18
2020-06-02T07:59:36.981072+00:00 heroku[web.1]: Starting …