Python 3.7.6 に brew upgrade したら python3 がターミナルで無効になった

Python 3.7.6 (default, Dec 27 2019, 09:51:07) に brew upgrade したら python3 がターミナルで無効になりました。

brew doctor によると

Warning: You have unlinked kegs in your Cellar.

Leaving kegs unlinked can lead to build-trouble and cause brews that depend on those kegs to fail to run properly once built. Run `brew link` on these:

python

texi2html

numpy

scipy

pyqt

らしいです。`brew link python` で再接続です。 

% brew link python
Linking /usr/local/Cellar/python/3.7.6... 24 symlinks created

% python
Python 2.7.17 (default, Dec 23 2019, 21:25:34) 
[GCC 4.2.1 Compatible Apple LLVM 11.0.0 (clang-1100.0.33.16)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

% python3
Python 3.7.6 (default, Dec 27 2019, 09:51:07) 
[Clang 11.0.0 (clang-1100.0.33.16)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>
B! LINE