pymysql.err.OperationalError: (1698, “Access denied for user ‘root‘@‘localhost‘“)

pymysql.err.OperationalError: (1698, “Access denied for user ‘root’@‘localhost’”)

$ sudo mysql -u root 

mysql> USE mysql;
mysql> UPDATE user SET plugin='mysql_native_password' WHERE User='root';
mysql> FLUSH PRIVILEGES;
mysql> exit;

$ service mysql restart