jupyter 启动报错解决办法 AttributeError: module ‘lib‘ has no attribute ‘X509_V_FLAG_CB_ISSUER_CHECK‘

jupyter notebook 突然启动不了，报错。上网搜了下，只需1行代码可解决，亲测可用！

报错内容：
Traceback (most recent call last):
File “D:\ANACONDA\Scripts\jupyter-notebook-script.py”, line 6, in
from notebook.notebookapp import main
File “D:\ANACONDA\lib\site-packages\notebook\notebookapp.py”, line 82, in
from .services.contents.manager import ContentsManager
File “D:\ANACONDA\lib\site-packages\notebook\services\contents\manager.py”, line 17, in
from nbformat import sign, validate as validate_nb, ValidationError
File “D:\ANACONDA\lib\site-packages\nbformat_init_.py”, line 33, in
from .validator import validate, ValidationError
File “D:\ANACONDA\lib\site-packages\nbformat\validator.py”, line 12, in
from jsonschema import ValidationError
File “D:\ANACONDA\lib\site-packages\jsonschema_init_.py”, line 18, in
from jsonschema.validators import (
File “D:\ANACONDA\lib\site-packages\jsonschema\validators.py”, line 8, in
import requests
File “D:\ANACONDA\lib\site-packages\requests_init_.py”, line 95, in
from urllib3.contrib import pyopenssl
File “D:\ANACONDA\lib\site-packages\urllib3\contrib\pyopenssl.py”, line 46, in
import OpenSSL.SSL
File “D:\ANACONDA\lib\site-packages\OpenSSL_init_.py”, line 8, in
from OpenSSL import crypto, SSL
File “D:\ANACONDA\lib\site-packages\OpenSSL\crypto.py”, line 1550, in
class X509StoreFlags(object):
File “D:\ANACONDA\lib\site-packages\OpenSSL\crypto.py”, line 1570, in X509StoreFlags
CB_ISSUER_CHECK = _lib.X509_V_FLAG_CB_ISSUER_CHECK
AttributeError: module ‘lib’ has no attribute ‘X509_V_FLAG_CB_ISSUER_CHECK’

**解决办法： **
pip install pyOpenSSL --upgrade