报错信息

    1. Retrying (Retry(total=4, connect=None, read=None, redirect=None)) after connecti
    2. on broken by 'ConnectTimeoutError(<pip._vendor.requests.packages.urllib3.connect
    3. ion.VerifiedHTTPSConnection object at 0x000001E8850E8320>, 'Connection to pypi.o
    4. rg timed out. (connect timeout=15)')': /simple/pip/

    解决方法一
    https://github.com/pypa/pip/issues/7424#issuecomment-589675343
    Step 1:
    Press Win+R to open Run, type in “regedit” and click OK.
    Step 2:
    Move to HKEY_CURRENT_USER/Software/Microsoft/Windows/Current Version/Internet Settings.
    Step 3:
    Find a file with the name ‘ProxyServer’ and delete it.
    Step 4:
    Open cmd
    Step 5:
    Fire a command ‘pip install flask-bcrypt’
    —— 只找到ProxyEnable，没有ProxyServer

    解决方法二
    给pip换源
    更换清华源 https://mirrors.tuna.tsinghua.edu.cn/help/pypi/
    或其他常用源 https://zhuanlan.zhihu.com/p/82714528
    —— 解决√