[PYTHON] Resolve the error that appears without setting the user after DLing mysql on MAC

Since mysql is a mac, I downloaded it with Homebrew. https://qiita.com/hkusu/items/cda3e8461e7a46ecf25d I didn't set the user name and it came out as mysql.infoschema.

Trying to change this mysql.infoschema to python,

rename user mysql.infoschema@localhost to python@localhost;

When I tried to change the user name with

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '.infoschema@localhost to python@localhost' at line 1

I got an error. In this case, it worked fine if I set it up instead of simply changing the user name.

Username settings https://qiita.com/YoshitakaOkada/items/f434bb0bc493ff9cd65b#%E3%83%A6%E3%83%BC%E3%82%B6%E4%BD%9C%E6%88%90