解决sqlalchemy连接数据库出现的报错
问题一：AttributeEror:“Nonetype” object has no attribute’encoding"
解决方法将utf-8 改为 utf8
问题二
Warning: (3719, “‘utf8’ is currently an alias for the character set UTF8MB3, but will be an alias for UTF8MB4 in a future release. Please consider using UTF8MB4 in order to be unambiguous.”) result = self._query(query)
解决办法 将utf8mb4
问题三：（1193，Unknown system variable ‘tx_isolation’).
出现此报错的原因是使用的mysql8.0 以前用的是：tx_isolation 现在用是： transaction_isolation
解决办法一：通过升级sqlalchemy的方法解决。pip install -i https://pypi.tuna.tsinghua.edu.cn/simple --upgrade sqlalchemy --ignore-installed
解决办法二：降低mysql的版本
