PooledDatabase's reuse_if_open setting is not working
And the usage of 
    
    with db:
        do_some_query()

still raise the MySQL gone away error f0a6f11aea19089af34befed2dab886706e1593a 
Why the super class of PooledDatabase is object? there is no connect function. dose the super class is Database?  `PooledDatabase` is used in multi-class inheritance later on in the module.
https://github.com/coleifer/peewee/blob/master/playhouse/pool.py#L122

the reuse_if_open params is no used